“Automake” in gnu Automake

“Automake” in gnu Automake
GNU Automake
For version 1.9.106, 18 September 2005
David MacKenzie
Tom Tromey
Alexandre Duret-Lutz
This manual is for GNU Automake (version 1.9.106, 18 September 2005), a program that
creates GNU standards-compliant Makefiles from template files.
c 1995, 1996, 1997, 1998, 1999, 2000, 2001, 2002, 2003, 2004, 2005 Free Software
Copyright Foundation, Inc.
Permission is granted to copy, distribute and/or modify this document under
the terms of the GNU Free Documentation License, Version 1.2 or any later
version published by the Free Software Foundation; with no Invariant Sections,
with the Front-Cover texts being “A GNU Manual,” and with the Back-Cover
Texts as in (a) below. A copy of the license is included in the section entitled
“GNU Free Documentation License.”
(a) The FSF’s Back-Cover Text is: “You have freedom to copy and modify
this GNU Manual, like GNU software. Copies published by the Free Software
Foundation raise funds for GNU development.”
Chapter 2: General ideas
1
1 Introduction
Automake is a tool for automatically generating ‘Makefile.in’s from files called
‘Makefile.am’. Each ‘Makefile.am’ is basically a series of make variable definitions1 , with
rules being thrown in occasionally. The generated ‘Makefile.in’s are compliant with the
GNU Makefile standards.
The GNU Makefile Standards Document (see section “Makefile Conventions” in The
GNU Coding Standards) is long, complicated, and subject to change. The goal of Automake
is to remove the burden of Makefile maintenance from the back of the individual GNU
maintainer (and put it on the back of the Automake maintainer).
The typical Automake input file is simply a series of variable definitions. Each such file
is processed to create a ‘Makefile.in’. There should generally be one ‘Makefile.am’ per
directory of a project.
Automake does constrain a project in certain ways; for instance, it assumes that the
project uses Autoconf (see section “Introduction” in The Autoconf Manual), and enforces
certain restrictions on the ‘configure.ac’ contents2 .
Automake requires perl in order to generate the ‘Makefile.in’s. However, the distributions created by Automake are fully GNU standards-compliant, and do not require perl
in order to be built.
Mail suggestions and bug reports for Automake to bug-automake@gnu.org.
2 General ideas
The following sections cover a few basic ideas that will help you understand how Automake
works.
2.1 General Operation
Automake works by reading a ‘Makefile.am’ and generating a ‘Makefile.in’. Certain
variables and rules defined in the ‘Makefile.am’ instruct Automake to generate more specialized code; for instance, a bin_PROGRAMS variable definition will cause rules for compiling
and linking programs to be generated.
The variable definitions and rules in the ‘Makefile.am’ are copied verbatim into the
generated file. This allows you to add arbitrary code into the generated ‘Makefile.in’.
For instance, the Automake distribution includes a non-standard rule for the cvs-dist
target, which the Automake maintainer uses to make distributions from his source control
system.
Note that most GNU make extensions are not recognized by Automake. Using such
extensions in a ‘Makefile.am’ will lead to errors or confusing behavior.
1
2
These variables are also called make macros in Make terminology, however in this manual we reserve the
term macro for Autoconf’s macros.
Older Autoconf versions used ‘configure.in’. Autoconf 2.50 and greater promotes ‘configure.ac’ over
‘configure.in’. The rest of this documentation will refer to ‘configure.ac’, but Automake also supports
‘configure.in’ for backward compatibility.
Chapter 2: General ideas
2
A special exception is that the GNU make append operator, ‘+=’, is supported. This
operator appends its right hand argument to the variable specified on the left. Automake
will translate the operator into an ordinary ‘=’ operator; ‘+=’ will thus work with any make
program.
Automake tries to keep comments grouped with any adjoining rules or variable definitions.
A rule defined in ‘Makefile.am’ generally overrides any such rule of a similar name
that would be automatically generated by automake. Although this is a supported feature,
it is generally best to avoid making use of it, as sometimes the generated rules are very
particular.
Similarly, a variable defined in ‘Makefile.am’ or AC_SUBSTed from ‘configure.ac’ will
override any definition of the variable that automake would ordinarily create. This feature
is more often useful than the ability to override a rule. Be warned that many of the variables
generated by automake are considered to be for internal use only, and their names might
change in future releases.
When examining a variable definition, Automake will recursively examine variables referenced in the definition. For example, if Automake is looking at the content of foo_SOURCES
in this snippet
xs = a.c b.c
foo_SOURCES = c.c $(xs)
it would use the files ‘a.c’, ‘b.c’, and ‘c.c’ as the contents of foo_SOURCES.
Automake also allows a form of comment that is not copied into the output; all lines
beginning with ‘##’ (leading spaces allowed) are completely ignored by Automake.
It is customary to make the first line of ‘Makefile.am’ read:
## Process this file with automake to produce Makefile.in
2.2 Strictness
While Automake is intended to be used by maintainers of GNU packages, it does make
some effort to accommodate those who wish to use it, but do not want to use all the GNU
conventions.
To this end, Automake supports three levels of strictness—the strictness indicating how
stringently Automake should check standards conformance.
The valid strictness levels are:
‘foreign’
Automake will check for only those things that are absolutely required for proper
operations. For instance, whereas GNU standards dictate the existence of a
‘NEWS’ file, it will not be required in this mode. The name comes from the fact
that Automake is intended to be used for GNU programs; these relaxed rules
are not the standard mode of operation.
‘gnu’
Automake will check—as much as possible—for compliance to the GNU standards for packages. This is the default.
‘gnits’
Automake will check for compliance to the as-yet-unwritten Gnits standards.
These are based on the GNU standards, but are even more detailed. Unless
Chapter 2: General ideas
3
you are a Gnits standards contributor, it is recommended that you avoid this
option until such time as the Gnits standard is actually published (which may
never happen).
See Chapter 20 [Gnits], page 82, for more information on the precise implications of the
strictness level.
Automake also has a special “cygnus” mode that is similar to strictness but handled
differently. This mode is useful for packages that are put into a “Cygnus” style tree (e.g.,
the GCC tree). See Chapter 21 [Cygnus], page 83, for more information on this mode.
2.3 The Uniform Naming Scheme
Automake variables generally follow a uniform naming scheme that makes it easy to decide
how programs (and other derived objects) are built, and how they are installed. This scheme
also supports configure time determination of what should be built.
At make time, certain variables are used to determine which objects are to be built. The
variable names are made of several pieces that are concatenated together.
The piece that tells automake what is being built is commonly called the primary. For
instance, the primary PROGRAMS holds a list of programs that are to be compiled and linked.
A different set of names is used to decide where the built objects should be installed.
These names are prefixes to the primary, and they indicate which standard directory should
be used as the installation directory. The standard directory names are given in the GNU
standards (see section “Directory Variables” in The GNU Coding Standards). Automake
extends this list with pkglibdir, pkgincludedir, and pkgdatadir; these are the same
as the non-‘pkg’ versions, but with ‘$(PACKAGE)’ appended. For instance, pkglibdir is
defined as ‘$(libdir)/$(PACKAGE)’.
For each primary, there is one additional variable named by prepending ‘EXTRA_’ to the
primary name. This variable is used to list objects that may or may not be built, depending
on what configure decides. This variable is required because Automake must statically
know the entire list of objects that may be built in order to generate a ‘Makefile.in’ that
will work in all cases.
For instance, cpio decides at configure time which programs should be built. Some of
the programs are installed in bindir, and some are installed in sbindir:
EXTRA_PROGRAMS = mt rmt
bin_PROGRAMS = cpio pax
sbin_PROGRAMS = $(MORE_PROGRAMS)
Defining a primary without a prefix as a variable, e.g., ‘PROGRAMS’, is an error.
Note that the common ‘dir’ suffix is left off when constructing the variable names; thus
one writes ‘bin_PROGRAMS’ and not ‘bindir_PROGRAMS’.
Not every sort of object can be installed in every directory. Automake will flag those
attempts it finds in error. Automake will also diagnose obvious misspellings in directory
names.
Sometimes the standard directories—even as augmented by Automake—are not enough.
In particular it is sometimes useful, for clarity, to install objects in a subdirectory of some
Chapter 2: General ideas
4
predefined directory. To this end, Automake allows you to extend the list of possible
installation directories. A given prefix (e.g., ‘zar’) is valid if a variable of the same name
with ‘dir’ appended is defined (e.g., ‘zardir’).
For instance, the following snippet will install ‘file.xml’ into ‘$(datadir)/xml’.
xmldir = $(datadir)/xml
xml_DATA = file.xml
The special prefix ‘noinst_’ indicates that the objects in question should be built but not
installed at all. This is usually used for objects required to build the rest of your package,
for instance static libraries (see Section 7.2 [A Library], page 34), or helper scripts.
The special prefix ‘check_’ indicates that the objects in question should not be built
until the ‘make check’ command is run. Those objects are not installed either.
The current primary names are ‘PROGRAMS’, ‘LIBRARIES’, ‘LISP’, ‘PYTHON’, ‘JAVA’,
‘SCRIPTS’, ‘DATA’, ‘HEADERS’, ‘MANS’, and ‘TEXINFOS’.
Some primaries also allow additional prefixes that control other aspects of automake’s
behavior. The currently defined prefixes are ‘dist_’, ‘nodist_’, and ‘nobase_’. These
prefixes are explained later (see Section 7.4 [Program and Library Variables], page 40).
2.4 How derived variables are named
Sometimes a Makefile variable name is derived from some text the maintainer supplies. For
instance, a program name listed in ‘_PROGRAMS’ is rewritten into the name of a ‘_SOURCES’
variable. In cases like this, Automake canonicalizes the text, so that program names and
the like do not have to follow Makefile variable naming rules. All characters in the name
except for letters, numbers, the strudel (@), and the underscore are turned into underscores
when making variable references.
For example, if your program is named ‘sniff-glue’, the derived variable name would
be ‘sniff_glue_SOURCES’, not ‘sniff-glue_SOURCES’. Similarly the sources for a library
named ‘libmumble++.a’ should be listed in the ‘libmumble___a_SOURCES’ variable.
The strudel is an addition, to make the use of Autoconf substitutions in variable names
less obfuscating.
2.5 Variables reserved for the user
Some ‘Makefile’ variables are reserved by the GNU Coding Standards for the use of the
“user”—the person building the package. For instance, CFLAGS is one such variable.
Sometimes package developers are tempted to set user variables such as CFLAGS because
it appears to make their job easier. However, the package itself should never set a user
variable, particularly not to include switches that are required for proper compilation of
the package. Since these variables are documented as being for the package builder, that
person rightfully expects to be able to override any of these variables at build time.
To get around this problem, Automake introduces an automake-specific shadow variable
for each user flag variable. (Shadow variables are not introduced for variables like CC, where
they would make no sense.) The shadow variable is named by prepending ‘AM_’ to the user
variable’s name. For instance, the shadow variable for YFLAGS is AM_YFLAGS. The package
maintainer—that is, the author(s) of the ‘Makefile.am’ and ‘configure.ac’ files—may
adjust these shadow variables however necessary.
Chapter 2: General ideas
5
See Section 26.5 [Flag Variables Ordering], page 96, for more discussion about these
variables and how they interact with per-target variables.
2.6 Programs automake might require
Automake sometimes requires helper programs so that the generated ‘Makefile’ can do its
work properly. There are a fairly large number of them, and we list them here.
Although all of these files are distributed and installed with Automake, a couple of them
are maintained separately. The Automake copies are updated before each release, but we
mention the original source in case you need more recent versions.
ansi2knr.c
ansi2knr.1
These two files are used by the automatic de-ANSI-fication support (see Section 7.14 [ANSI], page 55).
compile
This is a wrapper for compilers that do not accept options ‘-c’ and ‘-o’ at the
same time. It is only used when absolutely required. Such compilers are rare.
config.guess
config.sub
These two programs compute the canonical triplets for the given build, host, or
target architecture. These programs are updated regularly to support new architectures and fix probes broken by changes in new kernel versions. Each new
release of Automake comes with up-to-date copies of these programs. If your
copy of Automake is getting old, you are encouraged to fetch the latest versions of these files from http://savannah.gnu.org/cvs/?group=config before making a release.
config-ml.in
This file is not a program, it is a ‘configure’ fragment used for multilib support
(see Section 17.3 [Multilibs], page 81). This file is maintained in the GCC tree
at http://gcc.gnu.org/cvs.html.
depcomp
This program understands how to run a compiler so that it will generate not
only the desired output but also dependency information that is then used by
the automatic dependency tracking feature.
elisp-comp
This program is used to byte-compile Emacs Lisp code.
install-sh
This is a replacement for the install program that works on platforms where
install is unavailable or unusable.
mdate-sh
This script is used to generate a ‘version.texi’ file. It examines a file and
prints some date information about it.
missing
This wraps a number of programs that are typically only required by maintainers. If the program in question doesn’t exist, missing prints an informative
warning and attempts to fix things so that the build can continue.
Chapter 3: Some example packages
6
mkinstalldirs
This script used to be a wrapper around ‘mkdir -p’, which is not portable. Now
we use prefer to use ‘install-sh -d’ when configure finds that ‘mkdir -p’ does
not work, this makes one less script to distribute.
For backward compatibility ‘mkinstalldirs’ is still used and distributed when
automake finds it in a package. But it is no longer installed automatically, and
it should be safe to remove it.
py-compile
This is used to byte-compile Python scripts.
symlink-tree
This program duplicates a tree of directories, using symbolic links instead of
copying files. Such operation is performed when building multilibs (see Section 17.3 [Multilibs], page 81). This file is maintained in the GCC tree at
http://gcc.gnu.org/cvs.html.
texinfo.tex
Not a program, this file is required for ‘make dvi’, ‘make ps’ and ‘make pdf’
to work when Texinfo sources are in the package. The latest version can be
downloaded from http://www.gnu.org/software/texinfo/.
ylwrap
This program wraps lex and yacc and ensures that, for instance, multiple yacc
instances can be invoked in a single directory in parallel.
3 Some example packages
3.1 A simple example, start to finish
Let’s suppose you just finished writing zardoz, a program to make your head float from
vortex to vortex. You’ve been using Autoconf to provide a portability framework, but your
‘Makefile.in’s have been ad-hoc. You want to make them bulletproof, so you turn to
Automake.
The first step is to update your ‘configure.ac’ to include the commands that automake
needs. The way to do this is to add an AM_INIT_AUTOMAKE call just after AC_INIT:
AC_INIT(zardoz, 1.0)
AM_INIT_AUTOMAKE
...
Since your program doesn’t have any complicating factors (e.g., it doesn’t use gettext,
it doesn’t want to build a shared library), you’re done with this part. That was easy!
Now you must regenerate ‘configure’. But to do that, you’ll need to tell autoconf
how to find the new macro you’ve used. The easiest way to do this is to use the aclocal
program to generate your ‘aclocal.m4’ for you. But wait. . . maybe you already have an
‘aclocal.m4’, because you had to write some hairy macros for your program. The aclocal
program lets you put your own macros into ‘acinclude.m4’, so simply rename and then
run:
Chapter 3: Some example packages
7
mv aclocal.m4 acinclude.m4
aclocal
autoconf
Now it is time to write your ‘Makefile.am’ for zardoz. Since zardoz is a user program,
you want to install it where the rest of the user programs go: bindir. Additionally, zardoz
has some Texinfo documentation. Your ‘configure.ac’ script uses AC_REPLACE_FUNCS, so
you need to link against ‘$(LIBOBJS)’. So here’s what you’d write:
bin_PROGRAMS = zardoz
zardoz_SOURCES = main.c head.c float.c vortex9.c gun.c
zardoz_LDADD = $(LIBOBJS)
info_TEXINFOS = zardoz.texi
Now you can run ‘automake --add-missing’ to generate your ‘Makefile.in’ and grab
any auxiliary files you might need, and you’re done!
3.2 A classic program
GNU hello is renowned for its classic simplicity and versatility. This section shows how
Automake could be used with the GNU Hello package. The examples below are from the
latest beta version of GNU Hello, but with all of the maintainer-only code stripped out, as
well as all copyright comments.
Of course, GNU Hello is somewhat more featureful than your traditional two-liner. GNU
Hello is internationalized, does option processing, and has a manual and a test suite.
Here is the ‘configure.ac’ from GNU Hello. Please note: The calls to AC_INIT and
AM_INIT_AUTOMAKE in this example use a deprecated syntax. For the current approach, see
the description of AM_INIT_AUTOMAKE in Section 5.6.1 [Public macros], page 19.
dnl Process this file with autoconf to produce a configure script.
AC_INIT(src/hello.c)
AM_INIT_AUTOMAKE(hello, 1.3.11)
AM_CONFIG_HEADER(config.h)
dnl Set of available languages.
ALL_LINGUAS="de fr es ko nl no pl pt sl sv"
dnl Checks for programs.
AC_PROG_CC
AC_ISC_POSIX
dnl Checks for libraries.
dnl Checks for header files.
AC_STDC_HEADERS
AC_HAVE_HEADERS(string.h fcntl.h sys/file.h sys/param.h)
dnl Checks for library functions.
AC_FUNC_ALLOCA
Chapter 3: Some example packages
8
dnl Check for st_blksize in struct stat
AC_ST_BLKSIZE
dnl internationalization macros
AM_GNU_GETTEXT
AC_OUTPUT([Makefile doc/Makefile intl/Makefile po/Makefile.in \
src/Makefile tests/Makefile tests/hello],
[chmod +x tests/hello])
The ‘AM_’ macros are provided by Automake (or the Gettext library); the rest are standard Autoconf macros.
The top-level ‘Makefile.am’:
EXTRA_DIST = BUGS ChangeLog.O
SUBDIRS = doc intl po src tests
As you can see, all the work here is really done in subdirectories.
The ‘po’ and ‘intl’ directories are automatically generated using gettextize; they will
not be discussed here.
In ‘doc/Makefile.am’ we see:
info_TEXINFOS = hello.texi
hello_TEXINFOS = gpl.texi
This is sufficient to build, install, and distribute the GNU Hello manual.
Here is ‘tests/Makefile.am’:
TESTS = hello
EXTRA_DIST = hello.in testdata
The script ‘hello’ is generated by configure, and is the only test case. ‘make check’
will run this test.
Last we have ‘src/Makefile.am’, where all the real work is done:
bin_PROGRAMS = hello
hello_SOURCES = hello.c version.c getopt.c getopt1.c getopt.h system.h
hello_LDADD = $(INTLLIBS) $(ALLOCA)
localedir = $(datadir)/locale
INCLUDES = -I../intl -DLOCALEDIR=\"$(localedir)\"
3.3 Building true and false
Here is another, trickier example. It shows how to generate two programs (true and false)
from the same source file (‘true.c’). The difficult part is that each compilation of ‘true.c’
requires different cpp flags.
bin_PROGRAMS = true false
false_SOURCES =
false_LDADD = false.o
true.o: true.c
$(COMPILE) -DEXIT_CODE=0 -c true.c
Chapter 4: Creating a ‘Makefile.in’
9
false.o: true.c
$(COMPILE) -DEXIT_CODE=1 -o false.o -c true.c
Note that there is no true_SOURCES definition. Automake will implicitly assume that
there is a source file named ‘true.c’, and define rules to compile ‘true.o’ and link ‘true’.
The ‘true.o: true.c’ rule supplied by the above ‘Makefile.am’, will override the Automake generated rule to build ‘true.o’.
false_SOURCES is defined to be empty—that way no implicit value is substituted. Because we have not listed the source of ‘false’, we have to tell Automake how to link the
program. This is the purpose of the false_LDADD line. A false_DEPENDENCIES variable,
holding the dependencies of the ‘false’ target will be automatically generated by Automake
from the content of false_LDADD.
The above rules won’t work if your compiler doesn’t accept both ‘-c’ and ‘-o’. The
simplest fix for this is to introduce a bogus dependency (to avoid problems with a parallel
make):
true.o: true.c false.o
$(COMPILE) -DEXIT_CODE=0 -c true.c
false.o: true.c
$(COMPILE) -DEXIT_CODE=1 -c true.c && mv true.o false.o
Also, these explicit rules do not work if the de-ANSI-fication feature is used (see Section 7.14 [ANSI], page 55). Supporting de-ANSI-fication requires a little more work:
true_.o: true_.c false_.o
$(COMPILE) -DEXIT_CODE=0 -c true_.c
false_.o: true_.c
$(COMPILE) -DEXIT_CODE=1 -c true_.c && mv true_.o false_.o
As it turns out, there is also a much easier way to do this same task. Some of the above
techniques are useful enough that we’ve kept the example in the manual. However if you
were to build true and false in real life, you would probably use per-program compilation
flags, like so:
bin_PROGRAMS = false true
false_SOURCES = true.c
false_CPPFLAGS = -DEXIT_CODE=1
true_SOURCES = true.c
true_CPPFLAGS = -DEXIT_CODE=0
In this case Automake will cause ‘true.c’ to be compiled twice, with different flags.
De-ANSI-fication will work automatically. In this instance, the names of the object files
would be chosen by automake; they would be ‘false-true.o’ and ‘true-true.o’. (The
name of the object files rarely matters.)
Chapter 4: Creating a ‘Makefile.in’
10
4 Creating a ‘Makefile.in’
To create all the ‘Makefile.in’s for a package, run the automake program in the top
level directory, with no arguments. automake will automatically find each appropriate
‘Makefile.am’ (by scanning ‘configure.ac’; see Chapter 5 [configure], page 12) and generate the corresponding ‘Makefile.in’. Note that automake has a rather simplistic view of
what constitutes a package; it assumes that a package has only one ‘configure.ac’, at the
top. If your package has multiple ‘configure.ac’s, then you must run automake in each directory holding a ‘configure.ac’. (Alternatively, you may rely on Autoconf’s autoreconf,
which is able to recurse your package tree and run automake where appropriate.)
You can optionally give automake an argument; ‘.am’ is appended to the argument and
the result is used as the name of the input file. This feature is generally only used to automatically rebuild an out-of-date ‘Makefile.in’. Note that automake must always be run
from the topmost directory of a project, even if being used to regenerate the ‘Makefile.in’
in some subdirectory. This is necessary because automake must scan ‘configure.ac’, and
because automake uses the knowledge that a ‘Makefile.in’ is in a subdirectory to change
its behavior in some cases.
Automake will run autoconf to scan ‘configure.ac’ and its dependencies (i.e.,
‘aclocal.m4’ and any included file), therefore autoconf must be in your PATH. If there
is an AUTOCONF variable in your environment it will be used instead of autoconf, this
allows you to select a particular version of Autoconf. By the way, don’t misunderstand
this paragraph: automake runs autoconf to scan your ‘configure.ac’, this won’t build
‘configure’ and you still have to run autoconf yourself for this purpose.
automake accepts the following options:
-a
--add-missing
Automake requires certain common files to exist in certain situations; for instance, ‘config.guess’ is required if ‘configure.ac’ runs AC_CANONICAL_HOST.
Automake is distributed with several of these files (see Section 2.6 [Auxiliary
Programs], page 5); this option will cause the missing ones to be automatically
added to the package, whenever possible. In general if Automake tells you a
file is missing, try using this option. By default Automake tries to make a
symbolic link pointing to its own copy of the missing file; this can be changed
with ‘--copy’.
Many of the potentially-missing files are common scripts whose location may be
specified via the AC_CONFIG_AUX_DIR macro. Therefore, AC_CONFIG_AUX_DIR’s
setting affects whether a file is considered missing, and where the missing file
is added (see Section 5.2 [Optional], page 13).
--libdir=dir
Look for Automake data files in directory dir instead of in the installation
directory. This is typically used for debugging.
-c
--copy
When used with ‘--add-missing’, causes installed files to be copied. The
default is to make a symbolic link.
Chapter 4: Creating a ‘Makefile.in’
--cygnus
11
Causes the generated ‘Makefile.in’s to follow Cygnus rules, instead of GNU
or Gnits rules. For more information, see Chapter 21 [Cygnus], page 83.
-f
--force-missing
When used with ‘--add-missing’, causes standard files to be reinstalled even
if they already exist in the source tree. This involves removing the file from
the source tree before creating the new symlink (or, with ‘--copy’, copying the
new file).
--foreign
Set the global strictness to ‘foreign’. For more information, see Section 2.2
[Strictness], page 2.
--gnits
Set the global strictness to ‘gnits’. For more information, see Chapter 20
[Gnits], page 82.
--gnu
Set the global strictness to ‘gnu’. For more information, see Chapter 20 [Gnits],
page 82. This is the default strictness.
--help
Print a summary of the command line options and exit.
-i
--ignore-deps
This disables the dependency tracking feature in generated ‘Makefile’s; see
Section 7.15 [Dependencies], page 55.
--include-deps
This enables the dependency tracking feature. This feature is enabled by default. This option is provided for historical reasons only and probably should
not be used.
--no-force
Ordinarily automake creates all ‘Makefile.in’s mentioned in ‘configure.ac’.
This option causes it to only update those ‘Makefile.in’s that are out of date
with respect to one of their dependents.
-o dir
--output-dir=dir
Put the generated ‘Makefile.in’ in the directory dir. Ordinarily each
‘Makefile.in’ is created in the directory of the corresponding ‘Makefile.am’.
This option is deprecated and will be removed in a future release.
-v
--verbose
Cause Automake to print information about which files are being read or created.
--version
Print the version number of Automake and exit.
-W CATEGORY
--warnings=category
Output warnings falling in category. category can be one of:
Chapter 5: Scanning ‘configure.ac’
12
gnu
warnings related to the GNU Coding Standards (see section “Top”
in The GNU Coding Standards).
obsolete
obsolete features or constructions
override
user redefinitions of Automake rules or variables
portability
portability issues (e.g., use of make features that are known to be
not portable)
syntax
weird syntax, unused variables, typos
unsupported
unsupported or incomplete features
all
all the warnings
none
turn off all the warnings
error
treat warnings as errors
A category can be turned off by prefixing its name with ‘no-’. For instance,
‘-Wno-syntax’ will hide the warnings about unused variables.
The categories output by default are ‘syntax’ and ‘unsupported’. Additionally,
‘gnu’ is enabled in ‘--gnu’ and ‘--gnits’ strictness.
‘portability’ warnings are currently disabled by default, but they will be
enabled in ‘--gnu’ and ‘--gnits’ strictness in a future release.
The environment variable WARNINGS can contain a comma separated list of
categories to enable. It will be taken into account before the command-line
switches, this way ‘-Wnone’ will also ignore any warning category enabled by
WARNINGS. This variable is also used by other tools like autoconf; unknown
categories are ignored for this reason.
5 Scanning ‘configure.ac’
Automake scans the package’s ‘configure.ac’ to determine certain information about
the package. Some autoconf macros are required and some variables must be defined
in ‘configure.ac’. Automake will also use information from ‘configure.ac’ to further
tailor its output.
Automake also supplies some Autoconf macros to make the maintenance easier. These
macros can automatically be put into your ‘aclocal.m4’ using the aclocal program.
5.1 Configuration requirements
The one real requirement of Automake is that your ‘configure.ac’ call AM_INIT_AUTOMAKE.
This macro does several things that are required for proper Automake operation (see Section 5.6 [Macros], page 19).
Here are the other macros that Automake requires but which are not run by AM_INIT_
AUTOMAKE:
Chapter 5: Scanning ‘configure.ac’
13
AC_CONFIG_FILES
AC_OUTPUT
Automake uses these to determine which files to create (see section “Creating
Output Files” in The Autoconf Manual). A listed file is considered to be an Automake generated ‘Makefile’ if there exists a file with the same name and the
‘.am’ extension appended. Typically, ‘AC_CONFIG_FILES([foo/Makefile])’
will cause Automake to generate ‘foo/Makefile.in’ if ‘foo/Makefile.am’ exists.
When using AC_CONFIG_FILES with multiple input files, as in
AC_CONFIG_FILES([Makefile:top.in:Makefile.in:bot.in])
automake will generate the first ‘.in’ input file for which a ‘.am’ file exists. If
no such file exists the output file is not considered to be Automake generated.
Files created by AC_CONFIG_FILES are removed by make distclean.
5.2 Other things Automake recognizes
Every time Automake is run it calls Autoconf to trace ‘configure.ac’. This way it can
recognize the use of certain macros and tailor the generated ‘Makefile.in’ appropriately.
Currently recognized macros and their effects are:
AC_CONFIG_HEADERS
Automake will generate rules to rebuild these headers. Older versions of
Automake required the use of AM_CONFIG_HEADER (see Section 5.6 [Macros],
page 19); this is no longer the case today.
AC_CONFIG_LINKS
Automake will generate rules to remove ‘configure’ generated links on ‘make
distclean’ and to distribute named source files as part of ‘make dist’.
AC_CONFIG_AUX_DIR
Automake will look for various helper scripts, such as ‘install-sh’, in the directory named in this macro invocation. (The full list of scripts is: ‘config.guess’,
‘config.sub’, ‘depcomp’, ‘elisp-comp’, ‘compile’, ‘install-sh’, ‘ltmain.sh’,
‘mdate-sh’, ‘missing’, ‘mkinstalldirs’, ‘py-compile’, ‘texinfo.tex’, and
‘ylwrap’.) Not all scripts are always searched for; some scripts will only be
sought if the generated ‘Makefile.in’ requires them.
If AC_CONFIG_AUX_DIR is not given, the scripts are looked for in their standard
locations. For ‘mdate-sh’, ‘texinfo.tex’, and ‘ylwrap’, the standard location
is the source directory corresponding to the current ‘Makefile.am’. For the
rest, the standard location is the first one of ‘.’, ‘..’, or ‘../..’ (relative to the
top source directory) that provides any one of the helper scripts. See section
“Finding ‘configure’ Input” in The Autoconf Manual.
Required files from AC_CONFIG_AUX_DIR are automatically distributed, even if
there is no ‘Makefile.am’ in this directory.
Chapter 5: Scanning ‘configure.ac’
14
AC_CANONICAL_BUILD
AC_CANONICAL_HOST
AC_CANONICAL_TARGET
Automake will ensure that ‘config.guess’ and ‘config.sub’ exist. Also, the
‘Makefile’ variables build_triplet, host_triplet and target_triplet are
introduced. See section “Getting the Canonical System Type” in The Autoconf
Manual.
AC_LIBSOURCE
AC_LIBSOURCES
AC_LIBOBJ
Automake will automatically distribute any file listed in AC_LIBSOURCE or AC_
LIBSOURCES.
Note that the AC_LIBOBJ macro calls AC_LIBSOURCE. So if an Autoconf macro
is documented to call ‘AC_LIBOBJ([file])’, then ‘file.c’ will be distributed
automatically by Automake. This encompasses many macros like AC_FUNC_
ALLOCA, AC_FUNC_MEMCMP, AC_REPLACE_FUNCS, and others.
By the way, direct assignments to LIBOBJS are no longer supported. You should
always use AC_LIBOBJ for this purpose. See section “AC_LIBOBJ vs. LIBOBJS”
in The Autoconf Manual.
AC_PROG_RANLIB
This is required if any libraries are built in the package. See section “Particular
Program Checks” in The Autoconf Manual.
AC_PROG_CXX
This is required if any C++ source is included. See section “Particular Program
Checks” in The Autoconf Manual.
AC_PROG_F77
This is required if any Fortran 77 source is included. This macro is distributed
with Autoconf version 2.13 and later. See section “Particular Program Checks”
in The Autoconf Manual.
AC_PROG_FC
This is the newer interface to Fortran source, replacing the older F77 interfaces.
This macro is distributed with Autoconf version 2.50 and later. See section
“Particular Program Checks” in The Autoconf Manual.
AC_F77_LIBRARY_LDFLAGS
This is required for programs and shared libraries that are a mixture of languages that include Fortran 77 (see Section 7.11.4 [Mixing Fortran With C and
C++], page 52). See Section 5.6 [Autoconf macros supplied with Automake],
page 19.
AC_PROG_FC
This is required if any Fortran 90/95 source is included. This macro is distributed with Autoconf version 2.58 and later. See section “Particular Program
Checks” in The Autoconf Manual.
Chapter 5: Scanning ‘configure.ac’
15
AC_PROG_LIBTOOL
Automake will turn on processing for libtool (see section “Introduction” in
The Libtool Manual).
AC_PROG_YACC
If a Yacc source file is seen, then you must either use this macro or define the
variable YACC in ‘configure.ac’. The former is preferred (see section “Particular Program Checks” in The Autoconf Manual).
AC_PROG_LEX
If a Lex source file is seen, then this macro must be used. See section “Particular
Program Checks” in The Autoconf Manual.
AC_SUBST
The first argument is automatically defined as a variable in each generated
‘Makefile.in’. See section “Setting Output Variables” in The Autoconf Manual.
If the Autoconf manual says that a macro calls AC_SUBST for var, or defines the
output variable var then var will be defined in each ‘Makefile.in’ generated
by Automake. E.g. AC_PATH_XTRA defines X_CFLAGS and X_LIBS, so you can
use these variables in any ‘Makefile.am’ if AC_PATH_XTRA is called.
AM_C_PROTOTYPES
This is required when using automatic de-ANSI-fication; see Section 7.14
[ANSI], page 55.
AM_GNU_GETTEXT
This macro is required for packages that use GNU gettext (see Section 9.2
[gettext], page 63). It is distributed with gettext. If Automake sees this macro
it ensures that the package meets some of gettext’s requirements.
AM_MAINTAINER_MODE
This macro adds a ‘--enable-maintainer-mode’ option to configure. If this
is used, automake will cause “maintainer-only” rules to be turned off by default
in the generated ‘Makefile.in’s. This macro defines the MAINTAINER_MODE
conditional, which you can use in your own ‘Makefile.am’. See Section 26.2
[maintainer-mode], page 92.
m4_include
Files included by ‘configure.ac’ using this macro will be detected by Automake and automatically distributed. They will also appear as dependencies
in ‘Makefile’ rules.
m4_include is seldom used by ‘configure.ac’ authors, but can appear in
‘aclocal.m4’ when aclocal detects that some required macros come from files
local to your package (as opposed to macros installed in a system-wide directory,
see Section 5.3 [Invoking aclocal], page 15).
5.3 Auto-generating aclocal.m4
Automake includes a number of Autoconf macros that can be used in your package (see
Section 5.6 [Macros], page 19); some of them are actually required by Automake in certain
Chapter 5: Scanning ‘configure.ac’
16
situations. These macros must be defined in your ‘aclocal.m4’; otherwise they will not be
seen by autoconf.
The aclocal program will automatically generate ‘aclocal.m4’ files based on the contents of ‘configure.ac’. This provides a convenient way to get Automake-provided macros,
without having to search around. The aclocal mechanism allows other packages to supply
their own macros (see Section 5.7 [Extending aclocal], page 22). You can also use it to
maintain your own set of custom macros (see Section 5.8 [Local Macros], page 23).
At startup, aclocal scans all the ‘.m4’ files it can find, looking for macro definitions (see
Section 5.5 [Macro search path], page 17). Then it scans ‘configure.ac’. Any mention
of one of the macros found in the first step causes that macro, and any macros it in turn
requires, to be put into ‘aclocal.m4’.
Putting the file that contains the macro definition into ‘aclocal.m4’ is usually done by
copying the entire text of this file, including unused macro definitions as well as both ‘#’
and ‘dnl’ comments. If you want to make a comment that will be completely ignored by
aclocal, use ‘##’ as the comment leader.
When a file selected by aclocal is located in a subdirectory specified as a relative
search path with aclocal’s ‘-I’ argument, aclocal assumes the file belongs to the package
and uses m4_include instead of copying it into ‘aclocal.m4’. This makes the package
smaller, eases dependency tracking, and cause the file to be distributed automatically. (See
Section 5.8 [Local Macros], page 23, for an example.) Any macro that is found in a systemwide directory, or via an absolute search path will be copied. So use ‘-I ‘pwd‘/reldir’
instead of ‘-I reldir’ whenever some relative directory need to be considered outside the
package.
The contents of ‘acinclude.m4’, if this file exists, are also automatically included in
‘aclocal.m4’. We recommend against using ‘acinclude.m4’ in new packages (see Section 5.8 [Local Macros], page 23).
While computing ‘aclocal.m4’, aclocal runs autom4te (see section “Using Autom4te”
in The Autoconf Manual) in order to trace the macros that are really used, and omit from
‘aclocal.m4’ all macros that are mentioned but otherwise unexpanded (this can happen
when a macro is called conditionally). autom4te is expected to be in the PATH, just as
autoconf. Its location can be overridden using the AUTOM4TE environment variable.
5.4 aclocal options
aclocal accepts the following options:
--acdir=dir
Look for the macro files in dir instead of the installation directory. This is
typically used for debugging.
--help
Print a summary of the command line options and exit.
-I dir
Add the directory dir to the list of directories searched for ‘.m4’ files.
--force
Always overwrite the output file. The default is to overwrite the output file only
when really needed, i.e., when its contents changes or if one of its dependencies
is younger.
Chapter 5: Scanning ‘configure.ac’
17
--output=file
Cause the output to be put into file instead of ‘aclocal.m4’.
--print-ac-dir
Prints the name of the directory that aclocal will search to find third-party
‘.m4’ files. When this option is given, normal processing is suppressed. This
option can be used by a package to determine where to install a macro file.
--verbose
Print the names of the files it examines.
--version
Print the version number of Automake and exit.
5.5 Macro search path
By default, aclocal searches for ‘.m4’ files in the following directories, in this order:
acdir-APIVERSION
This is where the ‘.m4’ macros distributed with automake itself are stored.
APIVERSION depends on the automake release used; for automake 1.6.x,
APIVERSION = 1.6.
acdir
This directory is intended for third party ‘.m4’ files, and is configured when
automake itself is built. This is ‘@datadir@/aclocal/’, which typically expands
to ‘${prefix}/share/aclocal/’. To find the compiled-in value of acdir, use
the ‘--print-ac-dir’ option (see Section 5.4 [aclocal options], page 16).
As an example, suppose that automake-1.6.2 was configured with ‘--prefix=
/usr/local’. Then, the search path would be:
1. ‘/usr/local/share/aclocal-1.6/’
2. ‘/usr/local/share/aclocal/’
As explained in (see Section 5.4 [aclocal options], page 16), there are several options that
can be used to change or extend this search path.
5.5.1 Modifying the macro search path: --acdir
The most erroneous option to modify the search path is --acdir=dir , which changes default directory and drops the APIVERSION directory. For example, if one specifies -acdir=/opt/private/, then the search path becomes:
1. ‘/opt/private/’
This option, --acdir, is intended for use by the internal automake test suite only; it is
not ordinarily needed by end-users.
5.5.2 Modifying the macro search path: -I dir
Any extra directories specified using -I options (see Section 5.4 [aclocal options], page 16)
are prepended to this search list. Thus, aclocal -I /foo -I /bar results in the following
search path:
1. ‘/foo’
Chapter 5: Scanning ‘configure.ac’
18
2. ‘/bar’
3. acdir-APIVERSION
4. acdir
5.5.3 Modifying the macro search path: ‘dirlist’
There is a third mechanism for customizing the search path. If a ‘dirlist’ file exists in
acdir, then that file is assumed to contain a list of directories, one per line, to be added to
the search list. These directories are searched after all other directories.
For example, suppose ‘acdir /dirlist’ contains the following:
/test1
/test2
and that aclocal was called with the ‘-I /foo -I /bar’ options. Then, the search path
would be
1. /foo
2. /bar
3. acdir-APIVERSION
4. acdir
5. /test1
6. /test2
If the ‘--acdir=dir ’ option is used, then aclocal will search for the ‘dirlist’
file in dir. In the ‘--acdir=/opt/private/’ example above, aclocal would look for
‘/opt/private/dirlist’. Again, however, the ‘--acdir’ option is intended for use by the
internal automake test suite only; ‘--acdir’ is not ordinarily needed by end-users.
‘dirlist’ is useful in the following situation: suppose that automake version 1.6.2 is
installed with ‘--prefix=/usr’ by the system vendor. Thus, the default search directories
are
1. /usr/share/aclocal-1.6/
2. /usr/share/aclocal/
However, suppose further that many packages have been manually installed on the system, with $prefix=/usr/local, as is typical. In that case, many of these “extra” ‘.m4’ files
are in ‘/usr/local/share/aclocal’. The only way to force ‘/usr/bin/aclocal’ to find
these “extra” ‘.m4’ files is to always call ‘aclocal -I /usr/local/share/aclocal’. This
is inconvenient. With ‘dirlist’, one may create a file ‘/usr/share/aclocal/dirlist’
containing only the single line
/usr/local/share/aclocal
Now, the “default” search path on the affected system is
1. /usr/share/aclocal-1.6/
2. /usr/share/aclocal/
3. /usr/local/share/aclocal/
without the need for ‘-I’ options; ‘-I’ options can be reserved for project-specific needs
(‘my-source-dir/m4/’), rather than using it to work around local system-dependent tool
installation directories.
Chapter 5: Scanning ‘configure.ac’
19
Similarly, ‘dirlist’ can be handy if you have installed a local copy Automake on your
account and want aclocal to look for macros installed at other places on the system.
5.6 Autoconf macros supplied with Automake
Automake ships with several Autoconf macros that you can use from your ‘configure.ac’.
When you use one of them it will be included by aclocal in ‘aclocal.m4’.
5.6.1 Public macros
AM_C_PROTOTYPES
Check to see if function prototypes are understood by the compiler. If so, define
‘PROTOTYPES’ and set the output variables U and ANSI2KNR to the empty string.
Otherwise, set U to ‘_’ and ANSI2KNR to ‘./ansi2knr’. Automake uses these
values to implement automatic de-ANSI-fication.
AM_ENABLE_MULTILIB
This is used when a “multilib” library is being built. The first optional argument
is the name of the ‘Makefile’ being generated; it defaults to ‘Makefile’. The
second option argument is used to find the top source directory; it defaults to
the empty string (generally this should not be used unless you are familiar with
the internals). See Section 17.3 [Multilibs], page 81.
AM_INIT_AUTOMAKE([OPTIONS])
AM_INIT_AUTOMAKE(PACKAGE, VERSION, [NO-DEFINE])
Runs many macros required for proper operation of the generated Makefiles.
This macro has two forms, the first of which is preferred. In this form, AM_INIT_
AUTOMAKE is called with a single argument: a space-separated list of Automake
options that should be applied to every ‘Makefile.am’ in the tree. The effect is
as if each option were listed in AUTOMAKE_OPTIONS (see Chapter 16 [Options],
page 76).
The second, deprecated, form of AM_INIT_AUTOMAKE has two required arguments: the package and the version number. This form is obsolete because the
package and version can be obtained from Autoconf’s AC_INIT macro (which
itself has an old and a new form).
If your ‘configure.ac’ has:
AC_INIT(src/foo.c)
AM_INIT_AUTOMAKE(mumble, 1.5)
you can modernize it as follows:
AC_INIT(mumble, 1.5)
AC_CONFIG_SRCDIR(src/foo.c)
AM_INIT_AUTOMAKE
Note that if you’re upgrading your ‘configure.ac’ from an earlier version of
Automake, it is not always correct to simply move the package and version
arguments from AM_INIT_AUTOMAKE directly to AC_INIT, as in the example
above. The first argument to AC_INIT should be the name of your package
(e.g., ‘GNU Automake’), not the tarball name (e.g., ‘automake’) that you used
to pass to AM_INIT_AUTOMAKE. Autoconf tries to derive a tarball name from
Chapter 5: Scanning ‘configure.ac’
20
the package name, which should work for most but not all package names. (If
it doesn’t work for yours, you can use the four-argument form of AC_INIT to
provide the tarball name explicitly).
By default this macro AC_DEFINE’s PACKAGE and VERSION. This can be avoided
by passing the ‘no-define’ option, as in:
AM_INIT_AUTOMAKE([gnits 1.5 no-define dist-bzip2])
or by passing a third non-empty argument to the obsolete form.
AM_PATH_LISPDIR
Searches for the program emacs, and, if found, sets the output variable lispdir
to the full path to Emacs’ site-lisp directory.
Note that this test assumes the emacs found to be a version that supports
Emacs Lisp (such as gnu Emacs or XEmacs). Other emacsen can cause this
test to hang (some, like old versions of MicroEmacs, start up in interactive
mode, requiring C-x C-c to exit, which is hardly obvious for a non-emacs user).
In most cases, however, you should be able to use C-c to kill the test. In order
to avoid problems, you can set EMACS to “no” in the environment, or use the
‘--with-lispdir’ option to configure to explicitly set the correct path (if
you’re sure you have an emacs that supports Emacs Lisp.
AM_PROG_AS
Use this macro when you have assembly code in your project. This will choose
the assembler for you (by default the C compiler) and set CCAS, and will also
set CCASFLAGS if required.
AM_PROG_CC_C_O
This is like AC_PROG_CC_C_O, but it generates its results in the manner required
by automake. You must use this instead of AC_PROG_CC_C_O when you need
this functionality.
AM_PROG_LEX
Like AC_PROG_LEX (see section “Particular Program Checks” in The Autoconf
Manual), but uses the missing script on systems that do not have lex. HP-UX
10 is one such system.
AM_PROG_GCJ
This macro finds the gcj program or causes an error. It sets GCJ and GCJFLAGS.
gcj is the Java front-end to the GNU Compiler Collection.
AM_WITH_DMALLOC
Add support for the Dmalloc package. If the user runs configure with
‘--with-dmalloc’, then define WITH_DMALLOC and add ‘-ldmalloc’ to LIBS.
AM_WITH_REGEX
Adds ‘--with-regex’ to the configure command line. If specified (the default), then the ‘regex’ regular expression library is used, ‘regex.o’ is put into
LIBOBJS, and WITH_REGEX is defined. If ‘--without-regex’ is given, then the
rx regular expression library is used, and ‘rx.o’ is put into LIBOBJS.
Chapter 5: Scanning ‘configure.ac’
21
5.6.2 Obsolete macros
Although using some of the following macros was required in past releases, you should not
used any of them in new code. Running autoupdate should adjust your ‘configure.ac’
automatically (see section “Using autoupdate to Modernize ‘configure.ac’” in The Autoconf Manual).
AM_CONFIG_HEADER
Automake will generate rules to automatically regenerate the config header.
This obsolete macro is a synonym of AC_CONFIG_HEADERS today (see Section 5.2
[Optional], page 13).
AM_HEADER_TIOCGWINSZ_NEEDS_SYS_IOCTL
If the use of TIOCGWINSZ requires ‘<sys/ioctl.h>’, then define GWINSZ_IN_
SYS_IOCTL. Otherwise TIOCGWINSZ can be found in ‘<termios.h>’. This macro
is obsolete, you should use Autoconf’s AC_HEADER_TIOCGWINSZ instead.
AM_SYS_POSIX_TERMIOS
Check to see if POSIX termios headers and functions are available on the system. If so, set the shell variable am_cv_sys_posix_termios to ‘yes’. If not,
set the variable to ‘no’. This macro is obsolete, you should use Autoconf’s
AC_SYS_POSIX_TERMIOS instead.
5.6.3 Private macros
The following macros are private macros you should not call directly. They are called by
the other public macros when appropriate. Do not rely on them, as they might be changed
in a future version. Consider them as implementation details; or better, do not consider
them at all: skip this section!
_AM_DEPENDENCIES
AM_SET_DEPDIR
AM_DEP_TRACK
AM_OUTPUT_DEPENDENCY_COMMANDS
These macros are used to implement Automake’s automatic dependency tracking scheme. They are called automatically by automake when required, and
there should be no need to invoke them manually.
AM_MAKE_INCLUDE
This macro is used to discover how the user’s make handles include statements.
This macro is automatically invoked when needed; there should be no need to
invoke it manually.
AM_PROG_INSTALL_STRIP
This is used to find a version of install that can be used to strip a program
at installation time. This macro is automatically included when required.
AM_SANITY_CHECK
This checks to make sure that a file created in the build directory is newer than
a file in the source directory. This can fail on systems where the clock is set
incorrectly. This macro is automatically run from AM_INIT_AUTOMAKE.
Chapter 5: Scanning ‘configure.ac’
22
5.7 Writing your own aclocal macros
The aclocal program doesn’t have any built-in knowledge of any macros, so it is easy to
extend it with your own macros.
This can be used by libraries that want to supply their own Autoconf macros for use by
other programs. For instance, the gettext library supplies a macro AM_GNU_GETTEXT that
should be used by any package using gettext. When the library is installed, it installs this
macro so that aclocal will find it.
A macro file’s name should end in ‘.m4’.
Such files should be installed in
‘$(datadir)/aclocal’. This is as simple as writing:
aclocaldir = $(datadir)/aclocal
aclocal_DATA = mymacro.m4 myothermacro.m4
Please do use ‘$(datadir)/aclocal’, and not something based on the result of ‘aclocal
--print-ac-dir’. See Section 26.9 [Hard-Coded Install Paths], page 104, for arguments.
A file of macros should be a series of properly quoted AC_DEFUN’s (see section “Macro Definitions” in The Autoconf Manual). The aclocal programs also understands AC_REQUIRE
(see section “Prerequisite Macros” in The Autoconf Manual), so it is safe to put each macro
in a separate file. Each file should have no side effects but macro definitions. Especially,
any call to AC_PREREQ should be done inside the defined macro, not at the beginning of the
file.
Starting with Automake 1.8, aclocal will warn about all underquoted calls to AC_
DEFUN. We realize this will annoy a lot of people, because aclocal was not so strict in
the past and many third party macros are underquoted; and we have to apologize for this
temporary inconvenience. The reason we have to be stricter is that a future implementation
of aclocal (see Section 5.9 [Future of aclocal], page 24) will have to temporarily include all
these third party ‘.m4’ files, maybe several times, including even files that are not actually
needed. Doing so should alleviate many problems of the current implementation, however
it requires a stricter style from the macro authors. Hopefully it is easy to revise the existing
macros. For instance,
# bad style
AC_PREREQ(2.57)
AC_DEFUN(AX_FOOBAR,
[AC_REQUIRE([AX_SOMETHING])dnl
AX_FOO
AX_BAR
])
should be rewritten as
AC_DEFUN([AX_FOOBAR],
[AC_PREREQ(2.57)dnl
AC_REQUIRE([AX_SOMETHING])dnl
AX_FOO
AX_BAR
])
Wrapping the AC_PREREQ call inside the macro ensures that Autoconf 2.57 will not be
required if AX_FOOBAR is not actually used. Most importantly, quoting the first argument of
Chapter 5: Scanning ‘configure.ac’
23
AC_DEFUN allows the macro to be redefined or included twice (otherwise this first argument
would be expanded during the second definition).
If you have been directed here by the aclocal diagnostic but are not the maintainer
of the implicated macro, you will want to contact the maintainer of that macro. Please
make sure you have the last version of the macro and that the problem already hasn’t been
reported before doing so: people tend to work faster when they aren’t flooded by mails.
Another situation where aclocal is commonly used is to manage macros that are used
locally by the package, Section 5.8 [Local Macros], page 23.
5.8 Handling Local Macros
Feature tests offered by Autoconf do not cover all needs. People often have to supplement
existing tests with their own macros, or with third-party macros.
There are two ways to organize custom macros in a package.
The first possibility (the historical practice) is to list all your macros in ‘acinclude.m4’.
This file will be included in ‘aclocal.m4’ when you run aclocal, and its macro(s) will
henceforth be visible to autoconf. However if it contains numerous macros, it will rapidly
become difficult to maintain, and it will be almost impossible to share macros between
packages.
The second possibility, which we do recommend, is to write each macro in its own
file and gather all these files in a directory. This directory is usually called ‘m4/’. To build
‘aclocal.m4’, one should therefore instruct aclocal to scan ‘m4/’. From the command line,
this is done with ‘aclocal -I m4’. The top-level ‘Makefile.am’ should also be updated to
define
ACLOCAL_AMFLAGS = -I m4
ACLOCAL_AMFLAGS contains options to pass to aclocal when ‘aclocal.m4’ is to be rebuilt
by make. This line is also used by autoreconf (see section “Using autoreconf to Update
‘configure’ Scripts” in The Autoconf Manual) to run aclocal with suitable options, or
by autopoint (see section “Invoking the autopoint Program” in GNU gettext tools) and
gettextize (see section “Invoking the gettextize Program” in GNU gettext tools) to
locate the place where Gettext’s macros should be installed. So even if you do not really
care about the rebuild rules, you should define ACLOCAL_AMFLAGS.
When ‘aclocal -I m4’ is run, it will build a ‘aclocal.m4’ that m4_includes any file
from ‘m4/’ that defines a required macro. Macros not found locally will still be searched in
system-wide directories, as explained in Section 5.5 [Macro search path], page 17.
Custom macros should be distributed for the same reason that ‘configure.ac’ is: so
that other people have all the sources of your package if they want to work on it. Actually,
this distribution happens automatically because all m4_included files are distributed.
However there is no consensus on the distribution of third-party macros that your package
may use. Many libraries install their own macro in the system-wide aclocal directory
(see Section 5.7 [Extending aclocal], page 22). For instance, Guile ships with a file called
‘guile.m4’ that contains the macro GUILE_FLAGS that can be used to define setup compiler
and linker flags appropriate for using Guile. Using GUILE_FLAGS in ‘configure.ac’ will
cause aclocal to copy ‘guile.m4’ into ‘aclocal.m4’, but as ‘guile.m4’ is not part of the
project, it will not be distributed. Technically, that means a user who needs to rebuild
Chapter 6: Directories
24
‘aclocal.m4’ will have to install Guile first. This is probably OK, if Guile already is a
requirement to build the package. However, if Guile is only an optional feature, or if your
package might run on architectures where Guile cannot be installed, this requirement will
hinder development. An easy solution is to copy such third-party macros in your local ‘m4/’
directory so they get distributed.
5.9 The Future of aclocal
aclocal is expected to disappear. This feature really should not be offered by Automake.
Automake should focus on generating ‘Makefile’s; dealing with M4 macros really is Autoconf’s job. That some people install Automake just to use aclocal, but do not use
automake otherwise is an indication of how that feature is misplaced.
The new implementation will probably be done slightly differently. For instance it could
enforce the ‘m4/’-style layout discussed in Section 5.8 [Local Macros], page 23, and take
care of copying (and even updating) third-party macros from ‘/usr/share/aclocal/’ into
the local ‘m4/’ directory.
We have no idea when and how this will happen. This has been discussed several times
in the past, but someone still has to commit itself to that non-trivial task.
From the user point of view, aclocal’s removal might turn out to be painful. There is a
simple precaution that you may take to make that switch more seamless: never call aclocal
yourself. Keep this guy under the exclusive control of autoreconf and Automake’s rebuild
rules. Hopefully you won’t need to worry about things breaking, when aclocal disappears,
because everything will have been taken care of. If otherwise you used to call aclocal
directly yourself or from some script, you will quickly notice the change.
Many packages come with a script called ‘bootstrap.sh’ or ‘autogen.sh’, that will
just call aclocal, libtoolize, gettextize or autopoint, autoconf, autoheader, and
automake in the right order. Actually this is precisely what autoreconf can do for you. If
your package has such a ‘bootstrap.sh’ or ‘autogen.sh’ script, consider using autoreconf.
That should simplify its logic a lot (less things to maintain, yum!), it’s even likely you will
not need the script anymore, and more to the point you will not call aclocal directly
anymore.
For the time being, third-party packages should continue to install public macros into
‘/usr/share/aclocal/’. If aclocal is replaced by another tool it might make sense to
rename the directory, but supporting ‘/usr/share/aclocal/’ for backward compatibility
should be really easy provided all macros are properly written (see Section 5.7 [Extending
aclocal], page 22).
6 Directories
For simple projects that distributes all files in the same directory it is enough to have a
single ‘Makefile.am’ that builds everything in place.
In larger projects it is common to organize files in different directories, in a tree. For
instance one directory per program, per library or per module. The traditional approach is
to build these subdirectory recursively: each directory contains its ‘Makefile’ (generated
from ‘Makefile.am’), and when make is run from the top level directory it enters each
subdirectory in turn to build its contents.
Chapter 6: Directories
25
6.1 Recursing subdirectories
In packages with subdirectories, the top level ‘Makefile.am’ must tell Automake which
subdirectories are to be built. This is done via the SUBDIRS variable.
The SUBDIRS variable holds a list of subdirectories in which building of various sorts can
occur. The rules for many targets (e.g., all) in the generated ‘Makefile’ will run commands
both locally and in all specified subdirectories. Note that the directories listed in SUBDIRS
are not required to contain ‘Makefile.am’s; only ‘Makefile’s (after configuration). This
allows inclusion of libraries from packages that do not use Automake (such as gettext; see
also Section 22.2 [Third-Party Makefiles], page 85).
In packages that use subdirectories, the top-level ‘Makefile.am’ is often very short. For
instance, here is the ‘Makefile.am’ from the GNU Hello distribution:
EXTRA_DIST = BUGS ChangeLog.O README-alpha
SUBDIRS = doc intl po src tests
When Automake invokes make in a subdirectory, it uses the value of the MAKE variable.
It passes the value of the variable AM_MAKEFLAGS to the make invocation; this can be set in
‘Makefile.am’ if there are flags you must always pass to make.
The directories mentioned in SUBDIRS are usually direct children of the current directory,
each subdirectory containing its own ‘Makefile.am’ with a SUBDIRS pointing to deeper
subdirectories. Automake can be used to construct packages of arbitrary depth this way.
By default, Automake generates ‘Makefiles’ that work depth-first in postfix order: the
subdirectories are built before the current directory. However, it is possible to change this
ordering. You can do this by putting ‘.’ into SUBDIRS. For instance, putting ‘.’ first will
cause a prefix ordering of directories.
Using
SUBDIRS = lib src . test
will cause ‘lib/’ to be built before ‘src/’, then the current directory will be built, finally
the ‘test/’ directory will be built. It is customary to arrange test directories to be built
after everything else since they are meant to test what has been constructed.
All clean rules are run in reverse order of build rules.
6.2 Conditional Subdirectories
It is possible to define the SUBDIRS variable conditionally if, like in the case of GNU Inetutils,
you want to only build a subset of the entire package.
To illustrate how this works, let’s assume we have two directories ‘src/’ and ‘opt/’.
‘src/’ should always be built, but we want to decide in configure whether ‘opt/’ will be
built or not. (For this example we will assume that ‘opt/’ should be built when the variable
‘$want_opt’ was set to ‘yes’.)
Running make should thus recurse into ‘src/’ always, and then maybe in ‘opt/’.
However ‘make dist’ should always recurse into both ‘src/’ and ‘opt/’. Because ‘opt/’
should be distributed even if it is not needed in the current configuration. This means
‘opt/Makefile’ should be created unconditionally.
There are two ways to setup a project like this. You can use Automake conditionals
(see Chapter 19 [Conditionals], page 81) or use Autoconf AC_SUBST variables (see section
Chapter 6: Directories
26
“Setting Output Variables” in The Autoconf Manual). Using Automake conditionals is the
preferred solution. Before we illustrate these two possibility, let’s introduce DIST_SUBDIRS.
6.2.1 SUBDIRS vs. DIST_SUBDIRS
Automake considers two sets of directories, defined by the variables SUBDIRS and DIST_
SUBDIRS.
SUBDIRS contains the subdirectories of the current directory that must be built (see
Section 6.1 [Subdirectories], page 25). It must be defined manually; Automake will never
guess a directory is to be built. As we will see in the next two sections, it is possible to
define it conditionally so that some directory will be omitted from the build.
DIST_SUBDIRS is used in rules that need to recurse in all directories, even those that
have been conditionally left out of the build. Recall our example where we may not want
to build subdirectory ‘opt/’, but yet we want to distribute it? This is where DIST_SUBDIRS
come into play: ‘opt’ may not appear in SUBDIRS, but it must appear in DIST_SUBDIRS.
Precisely, DIST_SUBDIRS is used by ‘make maintainer-clean’, ‘make distclean’ and
‘make dist’. All other recursive rules use SUBDIRS.
If SUBDIRS is defined conditionally using Automake conditionals, Automake will define
DIST_SUBDIRS automatically from the possibles values of SUBDIRS in all conditions.
If SUBDIRS contains AC_SUBST variables, DIST_SUBDIRS will not be defined correctly
because Automake does not know the possible values of these variables. In this case DIST_
SUBDIRS needs to be defined manually.
6.2.2 Conditional subdirectories with AM_CONDITIONAL
‘configure’ should output the ‘Makefile’ for each directory and define a condition into
which ‘opt/’ should be built.
...
AM_CONDITIONAL([COND_OPT], [test "$want_opt" = yes])
AC_CONFIG_FILES([Makefile src/Makefile opt/Makefile])
...
Then SUBDIRS can be defined in the top-level ‘Makefile.am’ as follows.
if COND_OPT
MAYBE_OPT = opt
endif
SUBDIRS = src $(MAYBE_OPT)
As you can see, running make will rightly recurse into ‘src/’ and maybe ‘opt/’.
As you can’t see, running ‘make dist’ will recurse into both ‘src/’ and ‘opt/’ directories
because ‘make dist’, unlike ‘make all’, doesn’t use the SUBDIRS variable. It uses the DIST_
SUBDIRS variable.
In this case Automake will define ‘DIST_SUBDIRS = src opt’ automatically because it
knows that MAYBE_OPT can contain ‘opt’ in some condition.
6.2.3 Conditional Subdirectories with AC_SUBST
Another possibility is to define MAYBE_OPT from ‘./configure’ using AC_SUBST:
Chapter 6: Directories
27
...
if test "$want_opt" = yes; then
MAYBE_OPT=opt
else
MAYBE_OPT=
fi
AC_SUBST([MAYBE_OPT])
AC_CONFIG_FILES([Makefile src/Makefile opt/Makefile])
...
In this case the top-level ‘Makefile.am’ should look as follows.
SUBDIRS = src $(MAYBE_OPT)
DIST_SUBDIRS = src opt
The drawback is that since Automake cannot guess what the possible values of MAYBE_
OPT are, it is necessary to define DIST_SUBDIRS.
6.2.4 Non-configured Subdirectories
The semantic of DIST_SUBDIRS is often misunderstood by some users that try to configure
and build subdirectories conditionally. Here by configuring we mean creating the ‘Makefile’
(it might also involve running a nested configure script: this is a costly operation that
explains why people want to do it conditionally, but only the ‘Makefile’ is relevant to the
discussion).
The above examples all assume that every ‘Makefile’ is created, even in directories that
are not going to be built. The simple reason is that we want ‘make dist’ to distribute even
the directories that are not being built (e.g., platform-dependent code), hence ‘make dist’
must recurse into the subdirectory, hence this directory must be configured and appear in
DIST_SUBDIRS.
Building packages that do not configure every subdirectory is a tricky business, and we
do not recommend it to the novice as it is easy to produce an incomplete tarball by mistake.
We will not discuss this topic in depth here, yet for the adventurous here are a few rules to
remember.
• SUBDIRS should always be a subset of DIST_SUBDIRS.
It makes little sense to have a directory in SUBDIRS that is not in DIST_SUBDIRS. Think
of the former as a way to tell which directories listed in the latter should be built.
• Any directory listed in DIST_SUBDIRS and SUBDIRS must be configured.
I.e., the ‘Makefile’ must exists or the recursive make rules will not be able to process
the directory.
• Any configured directory must be listed in DIST_SUBDIRS.
So that the cleaning rule remove the generated ‘Makefile’s. It would be correct to see
DIST_SUBDIRS as a variable that lists all the directories that have been configured.
In order to prevent recursion in some non-configured directory you must therefore ensure
that this directory does not appear in DIST_SUBDIRS (and SUBDIRS). For instance, if you
Chapter 6: Directories
28
define SUBDIRS conditionally using AC_SUBST and do not define DIST_SUBDIRS explicitly, it
will be default to ‘$(SUBDIRS)’; another possibility is to force DIST_SUBDIRS = $(SUBDIRS).
Of course, directories that are omitted from DIST_SUBDIRS will not be distributed unless
you make other arrangements for this to happen (for instance, always running ‘make dist’
in a configuration where all directories are known to appear in DIST_SUBDIRS; or writing a
dist-hook target to distribute these directories).
In few packages, non-configured directories are not even expected to be distributed.
Although these packages do not require the aforementioned extra arrangements, there is
another pitfall. If the name of a directory appears in SUBDIRS or DIST_SUBDIRS, automake
will make sure the directory exists. Consequently automake cannot be run on such a
distribution when one directory has been omitted. One way to avoid this check is to use
the AC_SUBST method to declare conditional directories; since automake does not know the
values of AC_SUBST variables it cannot ensure the corresponding directory exist.
6.3 An Alternative Approach to Subdirectories
If you’ve ever read Peter Miller’s excellent paper, Recursive Make Considered Harmful, the
preceding sections on the use of subdirectories will probably come as unwelcome advice. For
those who haven’t read the paper, Miller’s main thesis is that recursive make invocations
are both slow and error-prone.
Automake provides sufficient cross-directory support3 to enable you to write a single
‘Makefile.am’ for a complex multi-directory package.
By default an installable file specified in a subdirectory will have its directory name
stripped before installation. For instance, in this example, the header file will be installed
as ‘$(includedir)/stdio.h’:
include_HEADERS = inc/stdio.h
However, the ‘nobase_’ prefix can be used to circumvent this path stripping. In this
example, the header file will be installed as ‘$(includedir)/sys/types.h’:
nobase_include_HEADERS = sys/types.h
‘nobase_’ should be specified first when used in conjunction with either ‘dist_’ or
‘nodist_’ (see Chapter 13 [Dist], page 70). For instance:
nobase_dist_pkgdata_DATA = images/vortex.pgm sounds/whirl.ogg
Finally, note that a variable using the ‘nobase_’ prefix can always be replaced by several variables, one for each destination directory (see Section 2.3 [Uniform], page 3). For
instance, the last example could be rewritten as follows:
imagesdir = $(pkgdatadir)/images
soundsdir = $(pkgdatadir)/sounds
dist_images_DATA = images/vortex.pgm
dist_sounds_DATA = sounds/whirl.ogg
This latter syntax makes it possible to change one destination directory without changing
the layout of the source tree.
3
We believe. This work is new and there are probably warts. See Chapter 1 [Introduction], page 1, for
information on reporting bugs.
Chapter 6: Directories
29
6.4 Nesting Packages
In the GNU Build System, packages can be nested to arbitrary depth. This means that a
package can embedded other packages with their own ‘configure’, ‘Makefile’s, etc.
These other packages should just appear as subdirectories of their parent package.
They must be listed in SUBDIRS like other ordinary directories. However the subpackage’s ‘Makefile’s should be output by its own ‘configure’ script, not by the parent’s
‘configure’. This is achieved using the AC_CONFIG_SUBDIRS Autoconf macro (see section
“Configuring Other Packages in Subdirectories” in The Autoconf Manual).
Here is an example package for an arm program that links with an hand library that is
a nested package in subdirectory ‘hand/’.
arm’s ‘configure.ac’:
AC_INIT([arm], [1.0])
AC_CONFIG_AUX_DIR([.])
AM_INIT_AUTOMAKE
AC_PROG_CC
AC_CONFIG_FILES([Makefile])
# Call hand’s ./configure script recursively.
AC_CONFIG_SUBDIRS([hand])
AC_OUTPUT
arm’s ‘Makefile.am’:
# Build the library in the hand subdirectory first.
SUBDIRS = hand
# Include hand’s header when compiling this directory.
AM_CPPFLAGS = -I$(srcdir)/hand
bin_PROGRAMS = arm
arm_SOURCES = arm.c
# link with the hand library.
arm_LDADD = hand/libhand.a
Now here is hand’s ‘hand/configure.ac’:
AC_INIT([hand], [1.2])
AC_CONFIG_AUX_DIR([.])
AM_INIT_AUTOMAKE
AC_PROG_CC
AC_PROG_RANLIB
AC_CONFIG_FILES([Makefile])
AC_OUTPUT
and its ‘hand/Makefile.am’:
lib_LIBRARIES = libhand.a
libhand_a_SOURCES = hand.c
When ‘make dist’ is run from the top-level directory it will create an archive
‘arm-1.0.tar.gz’ that contains the arm code as well as the ‘hand’ subdirectory. This
package can be built and installed like any ordinary package, with the usual ‘./configure
Chapter 7: Building Programs and Libraries
30
&& make && make install’ sequence (the hand subpackage will be built and installed by
the process).
When ‘make dist’ is run from the hand directory, it will create a self-contained
‘hand-1.2.tar.gz’ archive. So although it appears to be embedded in another package, it
can still be used separately.
The purpose of the ‘AC_CONFIG_AUX_DIR([.])’ instruction is to force Automake and
Autoconf into search auxiliary script in the current directory. For instance, this means
that there will be two copies of ‘install-sh’: one in the top-level of the arm package, and
another one in the ‘hand/’ subdirectory for the hand package.
The historical default is to search these auxiliary scripts in the immediate parent and
grand-parent directories. So if the ‘AC_CONFIG_AUX_DIR([.])’ line was removed from
‘hand/configure.ac’, that subpackage would share the auxiliary script of the arm package.
This may looks like a gain in size (a few kilobytes), but it is actually a loss of modularity
as the hand subpackage is no longer self-contained (‘make dist’ in the subdirectory will not
work anymore).
Packages that do not use Automake need more work to be integrated this way. See
Section 22.2 [Third-Party Makefiles], page 85.
7 Building Programs and Libraries
A large part of Automake’s functionality is dedicated to making it easy to build programs
and libraries.
7.1 Building a program
In order to build a program, you need to tell Automake which sources are part of it, and
which libraries it should be linked with.
This section also covers conditional compilation of sources or programs. Most of the
comments about these also apply to libraries (see Section 7.2 [A Library], page 34) and
libtool libraries (see Section 7.3 [A Shared Library], page 34).
7.1.1 Defining program sources
In a directory containing source that gets built into a program (as opposed to a library or
a script), the PROGRAMS primary is used. Programs can be installed in bindir, sbindir,
libexecdir, pkglibdir, or not at all (noinst_). They can also be built only for ‘make
check’, in which case the prefix is ‘check_’.
For instance:
bin_PROGRAMS = hello
In this simple case, the resulting ‘Makefile.in’ will contain code to generate a program
named hello.
Associated with each program are several assisting variables that are named after the
program. These variables are all optional, and have reasonable defaults. Each variable, its
use, and default is spelled out below; we use the “hello” example throughout.
The variable hello_SOURCES is used to specify which source files get built into an executable:
Chapter 7: Building Programs and Libraries
31
hello_SOURCES = hello.c version.c getopt.c getopt1.c getopt.h system.h
This causes each mentioned ‘.c’ file to be compiled into the corresponding ‘.o’. Then
all are linked to produce ‘hello’.
If hello_SOURCES is not specified, then it defaults to the single file ‘hello.c’ (see Section 7.5 [Default SOURCES], page 43).
Multiple programs can be built in a single directory. Multiple programs can share a
single source file, which must be listed in each _SOURCES definition.
Header files listed in a _SOURCES definition will be included in the distribution but
otherwise ignored. In case it isn’t obvious, you should not include the header file generated
by ‘configure’ in a _SOURCES variable; this file should not be distributed. Lex (‘.l’) and
Yacc (‘.y’) files can also be listed; see Section 7.8 [Yacc and Lex], page 47.
7.1.2 Linking the program
If you need to link against libraries that are not found by configure, you can use LDADD
to do so. This variable is used to specify additional objects or libraries to link with; it is
inappropriate for specifying specific linker flags, you should use AM_LDFLAGS for this purpose.
Sometimes, multiple programs are built in one directory but do not share the same
link-time requirements. In this case, you can use the prog _LDADD variable (where prog is
the name of the program as it appears in some _PROGRAMS variable, and usually written in
lowercase) to override the global LDADD. If this variable exists for a given program, then
that program is not linked using LDADD.
For instance, in GNU cpio, pax, cpio and mt are linked against the library ‘libcpio.a’.
However, rmt is built in the same directory, and has no such link requirement. Also, mt and
rmt are only built on certain architectures. Here is what cpio’s ‘src/Makefile.am’ looks
like (abridged):
bin_PROGRAMS = cpio pax $(MT)
libexec_PROGRAMS = $(RMT)
EXTRA_PROGRAMS = mt rmt
LDADD = ../lib/libcpio.a $(INTLLIBS)
rmt_LDADD =
cpio_SOURCES = ...
pax_SOURCES = ...
mt_SOURCES = ...
rmt_SOURCES = ...
prog _LDADD is inappropriate for passing program-specific linker flags (except for ‘-l’,
‘-L’, ‘-dlopen’ and ‘-dlpreopen’). So, use the prog _LDFLAGS variable for this purpose.
It is also occasionally useful to have a program depend on some other target that is not
actually part of that program. This can be done using the prog _DEPENDENCIES variable.
Each program depends on the contents of such a variable, but no further interpretation is
done.
If prog _DEPENDENCIES is not supplied, it is computed by Automake. The automaticallyassigned value is the contents of prog _LDADD, with most configure substitutions, ‘-l’, ‘-L’,
Chapter 7: Building Programs and Libraries
32
‘-dlopen’ and ‘-dlpreopen’ options removed. The configure substitutions that are left in
are only ‘$(LIBOBJS)’ and ‘$(ALLOCA)’; these are left because it is known that they will
not cause an invalid value for prog _DEPENDENCIES to be generated.
7.1.3 Conditional compilation of sources
You can’t put a configure substitution (e.g., ‘@FOO@’ or ‘$(FOO)’ where FOO is defined via
AC_SUBST) into a _SOURCES variable. The reason for this is a bit hard to explain, but suffice
to say that it simply won’t work. Automake will give an error if you try to do this.
Fortunately there are two other ways to achieve the same result. One is to use configure
substitutions in _LDADD variables, the other is to use an Automake conditional.
7.1.3.1 Conditional compilation using _LDADD substitutions
Automake must know all the source files that could possibly go into a program, even if
not all the files are built in every circumstance. Any files that are only conditionally built
should be listed in the appropriate EXTRA_ variable. For instance, if ‘hello-linux.c’ or
‘hello-generic.c’ were conditionally included in hello, the ‘Makefile.am’ would contain:
bin_PROGRAMS = hello
hello_SOURCES = hello-common.c
EXTRA_hello_SOURCES = hello-linux.c hello-generic.c
hello_LDADD = $(HELLO_SYSTEM)
hello_DEPENDENCIES = $(HELLO_SYSTEM)
You can then setup the ‘$(HELLO_SYSTEM)’ substitution from ‘configure.ac’:
...
case $host in
*linux*) HELLO_SYSTEM=’hello-linux.$(OBJEXT)’ ;;
*)
HELLO_SYSTEM=’hello-generic.$(OBJEXT)’ ;;
esac
AC_SUBST([HELLO_SYSTEM])
...
In this case, the variable HELLO_SYSTEM should be replaced by either ‘hello-linux.o’
or ‘hello-generic.o’, and added to both hello_DEPENDENCIES and hello_LDADD in order
to be built and linked in.
7.1.3.2 Conditional compilation using Automake conditionals
An often simpler way to compile source files conditionally is to use Automake conditionals.
For instance, you could use this ‘Makefile.am’ construct to build the same ‘hello’ example:
bin_PROGRAMS = hello
if LINUX
hello_SOURCES = hello-linux.c hello-common.c
else
hello_SOURCES = hello-generic.c hello-common.c
endif
In this case, ‘configure.ac’ should setup the LINUX conditional using AM_CONDITIONAL
(see Chapter 19 [Conditionals], page 81).
Chapter 7: Building Programs and Libraries
33
When using conditionals like this you don’t need to use the EXTRA_ variable, because
Automake will examine the contents of each variable to construct the complete list of source
files.
If your program uses a lot of files, you will probably prefer a conditional ‘+=’.
bin_PROGRAMS = hello
hello_SOURCES = hello-common.c
if LINUX
hello_SOURCES += hello-linux.c
else
hello_SOURCES += hello-generic.c
endif
7.1.4 Conditional compilation of programs
Sometimes it is useful to determine the programs that are to be built at configure time.
For instance, GNU cpio only builds mt and rmt under special circumstances. The means
to achieve conditional compilation of programs are the same you can use to compile source
files conditionally: substitutions or conditionals.
7.1.4.1 Conditional programs using configure substitutions
In this case, you must notify Automake of all the programs that can possibly be built,
but at the same time cause the generated ‘Makefile.in’ to use the programs specified
by configure. This is done by having configure substitute values into each _PROGRAMS
definition, while listing all optionally built programs in EXTRA_PROGRAMS.
bin_PROGRAMS = cpio pax $(MT)
libexec_PROGRAMS = $(RMT)
EXTRA_PROGRAMS = mt rmt
As explained in Section 7.16 [EXEEXT], page 56, Automake will rewrite bin_PROGRAMS,
libexec_PROGRAMS, and EXTRA_PROGRAMS, appending ‘$(EXEEXT)’ to each binary. Obviously it cannot rewrite values obtained at run-time through configure substitutions,
therefore you should take care of appending ‘$(EXEEXT)’ yourself, as in ‘AC_SUBST([MT],
[’mt${EXEEXT}’])’.
7.1.4.2 Conditional programs using Automake conditionals
You can also use Automake conditionals (see Chapter 19 [Conditionals], page 81) to select
programs to be built. In this case you don’t have to worry about ‘$(EXEEXT)’ or EXTRA_
PROGRAMS.
bin_PROGRAMS = cpio pax
if WANT_MT
bin_PROGRAMS += mt
endif
if WANT_RMT
libexec_PROGRAMS = rmt
endif
Chapter 7: Building Programs and Libraries
34
7.2 Building a library
Building a library is much like building a program. In this case, the name of the primary
is LIBRARIES. Libraries can be installed in libdir or pkglibdir.
See Section 7.3 [A Shared Library], page 34, for information on how to build shared
libraries using libtool and the LTLIBRARIES primary.
Each _LIBRARIES variable is a list of the libraries to be built. For instance, to create a
library named ‘libcpio.a’, but not install it, you would write:
noinst_LIBRARIES = libcpio.a
libcpio_a_SOURCES = ...
The sources that go into a library are determined exactly as they are for programs,
via the _SOURCES variables. Note that the library name is canonicalized (see Section 2.4
[Canonicalization], page 4), so the _SOURCES variable corresponding to ‘libcpio.a’ is
‘libcpio_a_SOURCES’, not ‘libcpio.a_SOURCES’.
Extra objects can be added to a library using the library _LIBADD variable. This should
be used for objects determined by configure. Again from cpio:
libcpio_a_LIBADD = $(LIBOBJS) $(ALLOCA)
In addition, sources for extra objects that will not exist until configure-time must be
added to the BUILT_SOURCES variable (see Section 8.4 [Sources], page 58).
Building a static library is done by compiling all object files, then by invoking ‘$(AR)
$(ARFLAGS)’ followed by the name of the library and the list of objects, and finally by calling
‘$(RANLIB)’ on that library. You should call AC_PROG_RANLIB from your ‘configure.ac’ to
define RANLIB (Automake will complain otherwise). AR and ARFLAGS default to ar and cru
respectively; you can override these two variables my setting them in your ‘Makefile.am’,
by AC_SUBSTing them from your ‘configure.ac’, or by defining a per-library maude_AR
variable (see Section 7.4 [Program and Library Variables], page 40).
Be careful when selecting library components conditionally. Because building an empty
library is not portable, you should ensure that any library contains always at least one
object.
To use a static library when building a program, add it to LDADD for this program. In
the following example, the program ‘cpio’ is statically linked with the library ‘libcpio.a’.
noinst_LIBRARIES = libcpio.a
libcpio_a_SOURCES = ...
bin_PROGRAMS = cpio
cpio_SOURCES = cpio.c ...
cpio_LDADD = libcpio.a
7.3 Building a Shared Library
Building shared libraries portably is a relatively complex matter. For this reason, GNU
Libtool (see section “Introduction” in The Libtool Manual) was created to help build shared
libraries in a platform-independent way.
Chapter 7: Building Programs and Libraries
35
7.3.1 The Libtool Concept
Libtool abstracts shared and static libraries into a unified concept henceforth called libtool
libraries. Libtool libraries are files using the ‘.la’ suffix, and can designate a static library, a shared library, or maybe both. Their exact nature cannot be determined until
‘./configure’ is run: not all platforms support all kinds of libraries, and users can explicitly select which libraries should be built. (However the package’s maintainers can tune the
default, see section “The AC_PROG_LIBTOOL macro” in The Libtool Manual.)
Because object files for shared and static libraries must be compiled differently, libtool
is also used during compilation. Object files built by libtool are called libtool objects: these
are files using the ‘.lo’ suffix. Libtool libraries are built from these libtool objects.
You should not assume anything about the structure of ‘.la’ or ‘.lo’ files and how libtool
constructs them: this is libtool’s concern, and the last thing one wants is to learn about
libtool’s guts. However the existence of these files matters, because they are used as targets
and dependencies in ‘Makefile’s rules when building libtool libraries. There are situations
where you may have to refer to these, for instance when expressing dependencies for building
source files conditionally (see Section 7.3.4 [Conditional Libtool Sources], page 37).
People considering writing a plug-in system, with dynamically loaded modules, should
look into ‘libltdl’: libtool’s dlopening library (see section “Using libltdl” in The Libtool
Manual). This offers a portable dlopening facility to load libtool libraries dynamically, and
can also achieve static linking where unavoidable.
Before we discuss how to use libtool with Automake in details, it should be noted that
the libtool manual also has a section about how to use Automake with libtool (see section
“Using Automake with Libtool” in The Libtool Manual).
7.3.2 Building Libtool Libraries
Automake uses libtool to build libraries declared with the LTLIBRARIES primary. Each
_LTLIBRARIES variable is a list of libtool libraries to build. For instance, to create a libtool
library named ‘libgettext.la’, and install it in libdir, write:
lib_LTLIBRARIES = libgettext.la
libgettext_la_SOURCES = gettext.c gettext.h ...
Automake predefines the variable pkglibdir, so you can use pkglib_LTLIBRARIES to
install libraries in ‘$(libdir)/@PACKAGE@/’.
If ‘gettext.h’ is a public header file that needs to be installed in order for people to
use the library, it should be declared using a _HEADERS variable, not in libgettext_la_
SOURCES. Headers listed in the latter should be internal headers that are not part of the
public interface.
lib_LTLIBRARIES = libgettext.la
libgettext_la_SOURCES = gettext.c ...
include_HEADERS = gettext.h ...
A package can build and install such a library along with other programs that use it.
This dependency should be specified using LDADD. The following example builds a program
named ‘hello’ that is linked with ‘libgettext.la’.
lib_LTLIBRARIES = libgettext.la
libgettext_la_SOURCES = gettext.c ...
Chapter 7: Building Programs and Libraries
36
bin_PROGRAMS = hello
hello_SOURCES = hello.c ...
hello_LDADD = libgettext.la
Whether ‘hello’ is statically or dynamically linked with ‘libgettext.la’ is not yet known:
this will depend on the configuration of libtool and the capabilities of the host.
7.3.3 Building Libtool Libraries Conditionally
Like conditional programs (see Section 7.1.4 [Conditional Programs], page 33), there are two
main ways to build conditional libraries: using Automake conditionals or using Autoconf
AC_SUBSTitutions.
The important implementation detail you have to be aware of is that the place where a
library will be installed matters to libtool: it needs to be indicated at link-time using the
‘-rpath’ option.
For libraries whose destination directory is known when Automake runs, Automake will
automatically supply the appropriate ‘-rpath’ option to libtool. This is the case for libraries
listed explicitly in some installable _LTLIBRARIES variables such as lib_LTLIBRARIES.
However, for libraries determined at configure time (and thus mentioned in EXTRA_
LTLIBRARIES), Automake does not know the final installation directory. For such libraries
you must add the ‘-rpath’ option to the appropriate _LDFLAGS variable by hand.
The examples below illustrate the differences between these two methods.
Here is an example where WANTEDLIBS is an AC_SUBSTed variable set at ‘./configure’time to either ‘libfoo.la’, ‘libbar.la’, both, or none. Although ‘$(WANTEDLIBS)’ appears
in the lib_LTLIBRARIES, Automake cannot guess it relates to ‘libfoo.la’ or ‘libbar.la’
by the time it creates the link rule for these two libraries. Therefore the ‘-rpath’ argument
must be explicitly supplied.
EXTRA_LTLIBRARIES
lib_LTLIBRARIES =
libfoo_la_SOURCES
libfoo_la_LDFLAGS
libbar_la_SOURCES
libbar_la_LDFLAGS
= libfoo.la libbar.la
$(WANTEDLIBS)
= foo.c ...
= -rpath ’$(libdir)’
= bar.c ...
= -rpath ’$(libdir)’
Here is how the same ‘Makefile.am’ would look using Automake conditionals named
WANT_LIBFOO and WANT_LIBBAR. Now Automake is able to compute the ‘-rpath’ setting
itself, because it’s clear that both libraries will end up in ‘$(libdir)’ if they are installed.
lib_LTLIBRARIES =
if WANT_LIBFOO
lib_LTLIBRARIES += libfoo.la
endif
if WANT_LIBBAR
lib_LTLIBRARIES += libbar.la
endif
libfoo_la_SOURCES = foo.c ...
libbar_la_SOURCES = bar.c ...
Chapter 7: Building Programs and Libraries
37
7.3.4 Libtool Libraries with Conditional Sources
Conditional compilation of sources in a library can be achieved in the same way as conditional compilation of sources in a program (see Section 7.1.3 [Conditional Sources], page 32).
The only difference is that _LIBADD should be used instead of _LDADD and that it should
mention libtool objects (‘.lo’ files).
So, to mimic the ‘hello’ example from Section 7.1.3 [Conditional Sources], page 32, we
could build a ‘libhello.la’ library using either ‘hello-linux.c’ or ‘hello-generic.c’
with the following ‘Makefile.am’.
lib_LTLIBRARIES = libhello.la
libhello_la_SOURCES = hello-common.c
EXTRA_libhello_la_SOURCES = hello-linux.c hello-generic.c
libhello_la_LIBADD = $(HELLO_SYSTEM)
libhello_la_DEPENDENCIES = $(HELLO_SYSTEM)
And make sure configure defines HELLO_SYSTEM as either ‘hello-linux.lo’ or ‘hellogeneric.lo’.
Or we could simply use an Automake conditional as follows.
lib_LTLIBRARIES = libhello.la
libhello_la_SOURCES = hello-common.c
if LINUX
libhello_la_SOURCES += hello-linux.c
else
libhello_la_SOURCES += hello-generic.c
endif
7.3.5 Libtool Convenience Libraries
Sometimes you want to build libtool libraries that should not be installed. These are called
libtool convenience libraries and are typically used to encapsulate many sublibraries, later
gathered into one big installed library.
Libtool convenience libraries are declared by directory-less variables such as noinst_
LTLIBRARIES, check_LTLIBRARIES, or even EXTRA_LTLIBRARIES. Unlike installed libtool
libraries they do not need an ‘-rpath’ flag at link time (actually this is the only difference).
Convenience libraries listed in noinst_LTLIBRARIES are always built. Those listed in
check_LTLIBRARIES are built only upon ‘make check’. Finally, libraries listed in EXTRA_
LTLIBRARIES are never built explicitly: Automake outputs rules to build them, but if the
library does not appear as a Makefile dependency anywhere it won’t be built (this is why
EXTRA_LTLIBRARIES is used for conditional compilation).
Here is a sample setup merging libtool convenience libraries from subdirectories into one
main ‘libtop.la’ library.
# -- Top-level Makefile.am -SUBDIRS = sub1 sub2 ...
lib_LTLIBRARIES = libtop.la
libtop_la_SOURCES =
libtop_la_LIBADD = \
sub1/libsub1.la \
Chapter 7: Building Programs and Libraries
38
sub2/libsub2.la \
...
# -- sub1/Makefile.am -noinst_LTLIBRARIES = libsub1.la
libsub1_la_SOURCES = ...
# -- sub2/Makefile.am -# showing nested convenience libraries
SUBDIRS = sub2.1 sub2.2 ...
noinst_LTLIBRARIES = libsub2.la
libsub2_la_SOURCES =
libsub2_la_LIBADD = \
sub21/libsub21.la \
sub22/libsub22.la \
...
When using such setup, beware that automake will assume ‘libtop.la’ is to be linked
with the C linker. This is because libtop_la_SOURCES is empty, so automake picks C as
default language. If libtop_la_SOURCES was not empty, automake would select the linker
as explained in Section 7.11.4.1 [How the Linker is Chosen], page 54.
If one of the sublibraries contains non-C source, it is important that the appropriate
linker be chosen. One way to achieve this is to pretend that there is such a non-C file
among the sources of the library, thus forcing automake to select the appropriate linker.
Here is the top-level ‘Makefile’ of our example updated to force C++ linking.
SUBDIRS = sub1 sub2 ...
lib_LTLIBRARIES = libtop.la
libtop_la_SOURCES =
# Dummy C++ source to cause C++ linking.
nodist_EXTRA_libtop_la_SOURCES = dummy.cxx
libtop_la_LIBADD = \
sub1/libsub1.la \
sub2/libsub2.la \
...
‘EXTRA_*_SOURCES’ variables are used to keep track of source files that might be compiled
(this is mostly useful when doing conditional compilation using AC_SUBST, see Section 7.3.4
[Conditional Libtool Sources], page 37), and the nodist_ prefix means the listed sources
are not to be distributed (see Section 7.4 [Program and Library Variables], page 40). In
effect the file ‘dummy.cxx’ does not need to exist in the source tree. Of course if you
have some real source file to list in libtop_la_SOURCES there is no point in cheating with
nodist_EXTRA_libtop_la_SOURCES.
7.3.6 Libtool Modules
These are libtool libraries meant to be dlopened. They are indicated to libtool by passing
‘-module’ at link-time.
pkglib_LTLIBRARIES = mymodule.la
mymodule_la_SOURCES = doit.c
Chapter 7: Building Programs and Libraries
39
mymodule_la_LDFLAGS = -module
Ordinarily, Automake requires that a library’s name starts with lib. However, when
building a dynamically loadable module you might wish to use a "nonstandard" name.
Automake will not complain about such nonstandard name if it knows the library being
built is a libtool module, i.e., if ‘-module’ explicitly appears in the library’s _LDFLAGS
variable (or in the common AM_LDFLAGS variable when no per-library _LDFLAGS variable is
defined).
As always, AC_SUBST variables are black boxes to Automake since their values are not yet
known when automake is run. Therefore if ‘-module’ is set via such a variable, Automake
cannot notice it and will proceed as if the library was an ordinary libtool library, with strict
naming.
If mymodule_la_SOURCES is not specified, then it defaults to the single file ‘mymodule.c’
(see Section 7.5 [Default SOURCES], page 43).
7.3.7
LIBADD and LDFLAGS
As shown in previous sections, the ‘library _LIBADD’ variable should be used to list extra
libtool objects (‘.lo’ files) or libtool libraries (‘.la’) to add to library.
The ‘library _LDFLAGS’ variable is the place to list additional libtool flags, such as
‘-version-info’, ‘-static’, and a lot more. See section “Link mode” in The Libtool
Manual.
7.3.8 LTLIBOBJS and LTALLOCA
Where an ordinary library might include ‘$(LIBOBJS)’ or ‘$(ALLOCA)’ (see Section 7.6
[LIBOBJS], page 44), a libtool library must use ‘$(LTLIBOBJS)’ or ‘$(LTALLOCA)’. This is
required because the object files that libtool operates on do not necessarily end in ‘.o’.
Nowadays, the computation of LTLIBOBJS from LIBOBJS is performed automatically by
Autoconf (see section “AC_LIBOBJ vs. LIBOBJS” in The Autoconf Manual).
7.3.9 Common Issues Related to Libtool’s Use
7.3.9.1 ‘required file ‘./ltmain.sh’ not found’
Libtool comes with a tool called libtoolize that will install libtool’s supporting files into
a package. Running this command will install ‘ltmain.sh’. You should execute it before
aclocal and automake.
People upgrading old packages to newer autotools are likely to face this issue because
older Automake versions used to call libtoolize. Therefore old build scripts do not call
libtoolize.
Since Automake 1.6, it has been decided that running libtoolize was none of Automake’s business. Instead, that functionality has been moved into the autoreconf command (see section “Using autoreconf” in The Autoconf Manual). If you do not want to
remember what to run and when, just learn the autoreconf command. Hopefully, replacing
existing ‘bootstrap.sh’ or ‘autogen.sh’ scripts by a call to autoreconf should also free
you from any similar incompatible change in the future.
Chapter 7: Building Programs and Libraries
40
7.3.9.2 Objects ‘created with both libtool and without’
Sometimes, the same source file is used both to build a libtool library and to build another
non-libtool target (be it a program or another library).
Let’s consider the following ‘Makefile.am’.
bin_PROGRAMS = prog
prog_SOURCES = prog.c foo.c ...
lib_LTLIBRARIES = libfoo.la
libfoo_la_SOURCES = foo.c ...
(In this trivial case the issue could be avoided by linking ‘libfoo.la’ with ‘prog’ instead
of listing ‘foo.c’ in prog_SOURCES. But let’s assume we really want to keep ‘prog’ and
‘libfoo.la’ separate.)
Technically, it means that we should build ‘foo.$(OBJEXT)’ for ‘prog’, and ‘foo.lo’ for
‘libfoo.la’. The problem is that in the course of creating ‘foo.lo’, libtool may erase (or
replace) ‘foo.$(OBJEXT)’, and this cannot be avoided.
Therefore, when Automake detects this situation it will complain with a message such
as
object ‘foo.$(OBJEXT)’ created both with libtool and without
A workaround for this issue is to ensure that these two objects get different basenames.
As explained in Section 26.6 [renamed objects], page 98, this happens automatically when
per-targets flags are used.
bin_PROGRAMS = prog
prog_SOURCES = prog.c foo.c ...
prog_CFLAGS = $(AM_CFLAGS)
lib_LTLIBRARIES = libfoo.la
libfoo_la_SOURCES = foo.c ...
Adding ‘prog_CFLAGS = $(AM_CFLAGS)’ is almost a no-op, because when the prog_CFLAGS
is defined, it is used instead of AM_CFLAGS. However as a side effect it will cause ‘prog.c’
and ‘foo.c’ to be compiled as ‘prog-prog.$(OBJEXT)’ and ‘prog-foo.$(OBJEXT)’, which
solves the issue.
7.4 Program and Library Variables
Associated with each program are a collection of variables that can be used to modify how
that program is built. There is a similar list of such variables for each library. The canonical
name of the program (or library) is used as a base for naming these variables.
In the list below, we use the name “maude” to refer to the program or library. In your
‘Makefile.am’ you would replace this with the canonical name of your program. This list
also refers to “maude” as a program, but in general the same rules apply for both static and
dynamic libraries; the documentation below notes situations where programs and libraries
differ.
maude_SOURCES
This variable, if it exists, lists all the source files that are compiled to build the
program. These files are added to the distribution by default. When building
Chapter 7: Building Programs and Libraries
41
the program, Automake will cause each source file to be compiled to a single
‘.o’ file (or ‘.lo’ when using libtool). Normally these object files are named
after the source file, but other factors can change this. If a file in the _SOURCES
variable has an unrecognized extension, Automake will do one of two things
with it. If a suffix rule exists for turning files with the unrecognized extension
into ‘.o’ files, then automake will treat this file as it will any other source file
(see Section 7.13 [Support for Other Languages], page 54). Otherwise, the file
will be ignored as though it were a header file.
The prefixes dist_ and nodist_ can be used to control whether files listed
in a _SOURCES variable are distributed. dist_ is redundant, as sources are
distributed by default, but it can be specified for clarity if desired.
It is possible to have both dist_ and nodist_ variants of a given _SOURCES
variable at once; this lets you easily distribute some files and not others, for
instance:
nodist_maude_SOURCES = nodist.c
dist_maude_SOURCES = dist-me.c
By default the output file (on Unix systems, the ‘.o’ file) will be put into
the current build directory. However, if the option ‘subdir-objects’ is in
effect in the current directory then the ‘.o’ file will be put into the subdirectory named after the source file. For instance, with ‘subdir-objects’ enabled,
‘sub/dir/file.c’ will be compiled to ‘sub/dir/file.o’. Some people prefer this mode of operation. You can specify ‘subdir-objects’ in AUTOMAKE_
OPTIONS (see Chapter 16 [Options], page 76).
EXTRA_maude_SOURCES
Automake needs to know the list of files you intend to compile statically. For
one thing, this is the only way Automake has of knowing what sort of language
support a given ‘Makefile.in’ requires.4 This means that, for example, you
can’t put a configure substitution like ‘@my_sources@’ into a ‘_SOURCES’ variable. If you intend to conditionally compile source files and use ‘configure’
to substitute the appropriate object names into, e.g., _LDADD (see below), then
you should list the corresponding source files in the EXTRA_ variable.
This variable also supports dist_ and nodist_ prefixes. For instance, nodist_
EXTRA_maude_SOURCES would list extra sources that may need to be built, but
should not be distributed.
maude_AR
A static library is created by default by invoking ‘$(AR) $(ARFLAGS)’ followed
by the name of the library and then the objects being put into the library. You
can override this by setting the _AR variable. This is usually used with C++;
some C++ compilers require a special invocation in order to instantiate all the
templates that should go into a library. For instance, the SGI C++ compiler
likes this variable set like so:
libmaude_a_AR = $(CXX) -ar -o
4
There are other, more obscure reasons for this limitation as well.
Chapter 7: Building Programs and Libraries
42
maude_LIBADD
Extra objects can be added to a library using the _LIBADD variable. For instance, this should be used for objects determined by configure (see Section 7.2
[A Library], page 34).
In the case of libtool libraries, maude_LIBADD can also refer to other libtool
libraries.
maude_LDADD
Extra objects (‘*.$(OBJDIR)’) and libraries (‘*.a’, ‘*.la’) can be added to a
program by listing them in the _LDADD variable. For instance, this should be
used for objects determined by configure (see Section 7.1.2 [Linking], page 31).
_LDADD and _LIBADD are inappropriate for passing program-specific linker flags
(except for ‘-l’, ‘-L’, ‘-dlopen’ and ‘-dlpreopen’). Use the _LDFLAGS variable
for this purpose.
For instance, if your ‘configure.ac’ uses AC_PATH_XTRA, you could link your
program against the X libraries like so:
maude_LDADD = $(X_PRE_LIBS) $(X_LIBS) $(X_EXTRA_LIBS)
maude_LDFLAGS
This variable is used to pass extra flags to the link step of a program or a shared
library.
maude_DEPENDENCIES
It is also occasionally useful to have a program depend on some other target that is not actually part of that program. This can be done using the
‘_DEPENDENCIES’ variable. Each program depends on the contents of such a
variable, but no further interpretation is done.
If ‘_DEPENDENCIES’ is not supplied, it is computed by Automake. The
automatically-assigned value is the contents of ‘_LDADD’ or ‘_LIBADD’, with
most configure substitutions, ‘-l’, ‘-L’, ‘-dlopen’ and ‘-dlpreopen’ options
removed. The configure substitutions that are left in are only ‘$(LIBOBJS)’
and ‘$(ALLOCA)’; these are left because it is known that they will not cause an
invalid value for ‘_DEPENDENCIES’ to be generated.
maude_LINK
You can override the linker on a per-program basis. By default the linker is
chosen according to the languages used by the program. For instance, a program
that includes C++ source code would use the C++ compiler to link. The ‘_LINK’
variable must hold the name of a command that can be passed all the ‘.o’ file
names as arguments. Note that the name of the underlying program is not
passed to ‘_LINK’; typically one uses ‘$@’:
maude_LINK = $(CCLD) -magic -o $@
Chapter 7: Building Programs and Libraries
43
maude_CCASFLAGS
maude_CFLAGS
maude_CPPFLAGS
maude_CXXFLAGS
maude_FFLAGS
maude_GCJFLAGS
maude_LFLAGS
maude_OBJCFLAGS
maude_RFLAGS
maude_YFLAGS
Automake allows you to set compilation flags on a per-program (or per-library)
basis. A single source file can be included in several programs, and it will potentially be compiled with different flags for each program. This works for any language directly supported by Automake. These per-target compilation flags are
‘_CCASFLAGS’, ‘_CFLAGS’, ‘_CPPFLAGS’, ‘_CXXFLAGS’, ‘_FFLAGS’, ‘_GCJFLAGS’,
‘_LFLAGS’, ‘_OBJCFLAGS’, ‘_RFLAGS’, and ‘_YFLAGS’.
When using a per-target compilation flag, Automake will choose a different
name for the intermediate object files. Ordinarily a file like ‘sample.c’ will be
compiled to produce ‘sample.o’. However, if the program’s _CFLAGS variable
is set, then the object file will be named, for instance, ‘maude-sample.o’. (See
also Section 26.6 [renamed objects], page 98.)
In compilations with per-target flags, the ordinary ‘AM_’ form of the flags variable is not automatically included in the compilation (however, the user form of
the variable is included). So for instance, if you want the hypothetical ‘maude’
compilations to also use the value of AM_CFLAGS, you would need to write:
maude_CFLAGS = ... your flags ... $(AM_CFLAGS)
See Section 26.5 [Flag Variables Ordering], page 96, for more discussion about
the interaction between user variables, ‘AM_’ shadow variables, and per-target
variables.
maude_SHORTNAME
On some platforms the allowable file names are very short. In order to support
these systems and per-target compilation flags at the same time, Automake
allows you to set a “short name” that will influence how intermediate object
files are named. For instance, in the following example,
bin_PROGRAMS = maude
maude_CPPFLAGS = -DSOMEFLAG
maude_SHORTNAME = m
maude_SOURCES = sample.c ...
the object file would be named ‘m-sample.o’ rather than ‘maude-sample.o’.
This facility is rarely needed in practice, and we recommend avoiding it until
you find it is required.
Chapter 7: Building Programs and Libraries
44
7.5 Default _SOURCES
_SOURCES variables are used to specify source files of programs (see Section 7.1 [A Program], page 30), libraries (see Section 7.2 [A Library], page 34), and Libtool libraries (see
Section 7.3 [A Shared Library], page 34).
When no such variable is specified for a target, Automake will define one itself. The
default is to compile a single C file whose base name is the name of the target itself, with
any extension replaced by ‘.c’. (Defaulting to C is terrible but we are stuck with it for
historical reasons.)
For example if you have the following somewhere in your ‘Makefile.am’ with no corresponding libfoo_a_SOURCES:
lib_LIBRARIES = libfoo.a sub/libc++.a
‘libfoo.a’ will be built using a default source file named ‘libfoo.c’, and ‘sub/libc++.a’
will be built from ‘sub/libc++.c’. (In older versions ‘sub/libc++.a’ would be built from
‘sub_libc___a.c’, i.e., the default source was the canonized name of the target, with ‘.c’
appended. We believe the new behavior is more sensible, but for backward compatibility
automake will use the old name if a file or a rule with that name exist.)
Default sources are mainly useful in test suites, when building many tests programs each
from a single source. For instance, in
check_PROGRAMS = test1 test2 test3
‘test1’, ‘test2’, and ‘test3’ will be built from ‘test1.c’, ‘test2.c’, and ‘test3.c’.
Another case where is this convenient is building many Libtool modules (‘moduleN.la’),
each defined in its own file (‘moduleN.c’).
AM_LDFLAGS = -module
lib_LTLIBRARIES = module1.la module2.la module3.la
Finally, there is one situation where this default source computation needs to be avoided:
when a target should not be built from sources. We already saw such an example in
Section 3.3 [true], page 8; this happens when all the constituents of a target have already
been compiled and need just to be combined using a _LDADD variable. Then it is necessary
to define an empty _SOURCES variable, so that automake does not compute a default.
bin_PROGRAMS = target
target_SOURCES =
target_LDADD = libmain.a libmisc.a
7.6 Special handling for LIBOBJS and ALLOCA
The ‘$(LIBOBJS)’ and ‘$(ALLOCA)’ variables list object files that should be compiled into
the project to provide an implementation for functions that are missing or broken on the
host system. They are substituted by ‘configure’.
These variables are defined by Autoconf macros such as AC_LIBOBJ, AC_REPLACE_FUNCS
(see section “Generic Function Checks” in The Autoconf Manual), or AC_FUNC_ALLOCA (see
section “Particular Function Checks” in The Autoconf Manual). Many other Autoconf
macros call AC_LIBOBJ or AC_REPLACE_FUNCS to populate ‘$(LIBOBJS)’.
Using these variables is very similar to doing conditional compilation using AC_SUBST
variables, as described in Section 7.1.3 [Conditional Sources], page 32. That is, when building a program, ‘$(LIBOBJS)’ and ‘$(ALLOCA)’ should be added to the associated ‘*_LDADD’
Chapter 7: Building Programs and Libraries
45
variable, or to the ‘*_LIBADD’ variable when building a library. However there is no need
to list the corresponding sources in ‘EXTRA_*_SOURCES’ nor to define ‘*_DEPENDENCIES’.
Automake automatically adds ‘$(LIBOBJS)’ and ‘$(ALLOCA)’ to the dependencies, and it
will discover the list of corresponding source files automatically (by tracing the invocations
of the AC_LIBSOURCE Autoconf macros).
These variables are usually used to build a portability library that is linked with all the
programs of the project. We now review a sample setup. First, ‘configure.ac’ contains
some checks that affect either LIBOBJS or ALLOCA.
# configure.ac
...
AC_CONFIG_LIBOBJ_DIR([lib])
...
AC_FUNC_MALLOC
dnl May add malloc.$(OBJEXT) to LIBOBJS
AC_FUNC_MEMCMP
dnl May add memcmp.$(OBJEXT) to LIBOBJS
AC_REPLACE_FUNCS([strdup]) dnl May add strdup.$(OBJEXT) to LIBOBJS
AC_FUNC_ALLOCA
dnl May add alloca.$(OBJEXT) to ALLOCA
...
AC_CONFIG_FILES([
lib/Makefile
src/Makefile
])
AC_OUTPUT
The AC_CONFIG_LIBOBJ_DIR tells Autoconf that the source files of these object files are
to be found in the ‘lib/’ directory. Automake does not yet use this information; it knows
the source files are expected to be in the directory where the ‘$(LIBOBJS)’ and ‘$(ALLOCA)’
variables are used.
The ‘lib/’ directory should therefore contain ‘malloc.c’, ‘memcmp.c’, ‘strdup.c’,
‘alloca.c’. Here is its ‘Makefile.am’:
# lib/Makefile.am
noinst_LIBRARIES = libcompat.a
libcompat_a_SOURCES =
libcompat_a_LIBADD = $(LIBOBJS) $(ALLOCA)
The library can have any name, of course, and anyway it is not going to be installed:
it just holds the replacement versions of the missing or broken functions so we can later
link them in. In many projects also include extra functions, specific to the project, in that
library: they are simply added on the _SOURCES line.
There is a small trap here, though: ‘$(LIBOBJS)’ and ‘$(ALLOCA)’ might be empty, and
building an empty library is not portable. You should ensure that there is always something
to put in ‘libcompat.a’. Most projects will also add some utility functions in that directory,
and list them in libcompat_a_SOURCES, so in practice ‘libcompat.a’ cannot be empty.
Finally here is how this library could be used from the ‘src/’ directory.
# src/Makefile.am
# Link all programs in this directory with libcompat.a
Chapter 7: Building Programs and Libraries
46
LDADD = ../lib/libcompat.a
bin_PROGRAMS = tool1 tool2 ...
tool1_SOURCES = ...
tool2_SOURCES = ...
Please note it would be wrong to use the variables ‘$(LIBOBJS)’ or ‘$(ALLOCA)’ in
‘src/Makefile.am’, because these variables contains unprefixed object names, and, for
instance, ‘malloc.$(OBJEXT)’ is not buildable in the ‘src/’ directory. (Actually if you
try using ‘$(LIBOBJS)’ in ‘src/’, Automake will require a copy of ‘malloc.c’, ‘memcmp.c’,
‘strdup.c’, ‘alloca.c’ in ‘src/’ too.)
Because ‘$(LIBOBJS)’ and ‘$(ALLOCA)’ contain object file names that end with
‘.$(OBJEXT)’, they are not suitable for Libtool libraries (where the expected object
extension is ‘.lo’): LTLIBOBJS and LTALLOCA should be used instead.
LTLIBOBJS is defined automatically by Autoconf and should not be defined by hand (as
in the past), however at the time of writing LTALLOCA still needs to be defined from ALLOCA
manually. See section “AC_LIBOBJ vs. LIBOBJS” in The Autoconf Manual.
7.7 Variables used when building a program
Occasionally it is useful to know which ‘Makefile’ variables Automake uses for compilations;
for instance, you might need to do your own compilation in some special cases.
Some variables are inherited from Autoconf; these are CC, CFLAGS, CPPFLAGS, DEFS,
LDFLAGS, and LIBS.
There are some additional variables that Automake defines on its own:
AM_CPPFLAGS
The contents of this variable are passed to every compilation that invokes the
C preprocessor; it is a list of arguments to the preprocessor. For instance, ‘-I’
and ‘-D’ options should be listed here.
Automake already provides some ‘-I’ options automatically. In particular it
generates ‘-I$(srcdir)’, ‘-I.’, and a ‘-I’ pointing to the directory holding
‘config.h’ (if you’ve used AC_CONFIG_HEADERS or AM_CONFIG_HEADER). You
can disable the default ‘-I’ options using the ‘nostdinc’ option.
AM_CPPFLAGS is ignored in preference to a per-executable (or per-library) _
CPPFLAGS variable if it is defined.
INCLUDES
This does the same job as AM_CPPFLAGS (or any per-target _CPPFLAGS variable
if it is used). It is an older name for the same functionality. This variable is
deprecated; we suggest using AM_CPPFLAGS and per-target _CPPFLAGS instead.
AM_CFLAGS
This is the variable the ‘Makefile.am’ author can use to pass in additional C
compiler flags. It is more fully documented elsewhere. In some situations, this
is not used, in preference to the per-executable (or per-library) _CFLAGS.
COMPILE
This is the command used to actually compile a C source file. The file name is
appended to form the complete command line.
Chapter 7: Building Programs and Libraries
47
AM_LDFLAGS
This is the variable the ‘Makefile.am’ author can use to pass in additional linker
flags. In some situations, this is not used, in preference to the per-executable
(or per-library) _LDFLAGS.
LINK
This is the command used to actually link a C program. It already includes
‘-o $@’ and the usual variable references (for instance, CFLAGS); it takes as
“arguments” the names of the object files and libraries to link in.
7.8 Yacc and Lex support
Automake has somewhat idiosyncratic support for Yacc and Lex.
Automake assumes that the ‘.c’ file generated by yacc (or lex) should be named using
the basename of the input file. That is, for a yacc source file ‘foo.y’, Automake will
cause the intermediate file to be named ‘foo.c’ (as opposed to ‘y.tab.c’, which is more
traditional).
The extension of a yacc source file is used to determine the extension of the resulting C
or C++ file. Files with the extension ‘.y’ will be turned into ‘.c’ files; likewise, ‘.yy’ will
become ‘.cc’; ‘.y++’, ‘c++’; and ‘.yxx’, ‘.cxx’.
Likewise, lex source files can be used to generate C or C++; the extensions ‘.l’, ‘.ll’,
‘.l++’, and ‘.lxx’ are recognized.
You should never explicitly mention the intermediate (C or C++) file in any SOURCES
variable; only list the source file.
The intermediate files generated by yacc (or lex) will be included in any distribution
that is made. That way the user doesn’t need to have yacc or lex.
If a yacc source file is seen, then your ‘configure.ac’ must define the variable YACC.
This is most easily done by invoking the macro AC_PROG_YACC (see section “Particular
Program Checks” in The Autoconf Manual).
When yacc is invoked, it is passed YFLAGS and AM_YFLAGS. The former is a user variable
and the latter is intended for the ‘Makefile.am’ author.
AM_YFLAGS is usually used to pass the ‘-d’ option to yacc. Automake knows what this
means and will automatically adjust its rules to update and distribute the header file built
by ‘yacc -d’. What Automake cannot guess, though, is where this header will be used: it is
up to you to ensure the header gets built before it is first used. Typically this is necessary
in order for dependency tracking to work when the header is included by another file. The
common solution is listing the header file in BUILT_SOURCES (see Section 8.4 [Sources],
page 58) as follows.
BUILT_SOURCES = parser.h
AM_YFLAGS = -d
bin_PROGRAMS = foo
foo_SOURCES = ... parser.y ...
If a lex source file is seen, then your ‘configure.ac’ must define the variable LEX. You
can use AC_PROG_LEX to do this (see section “Particular Program Checks” in The Autoconf
Manual), but using AM_PROG_LEX macro (see Section 5.6 [Macros], page 19) is recommended.
When lex is invoked, it is passed LFLAGS and AM_LFLAGS. The former is a user variable
and the latter is intended for the ‘Makefile.am’ author.
Chapter 7: Building Programs and Libraries
48
Automake makes it possible to include multiple yacc (or lex) source files in a single
program. When there is more than one distinct yacc (or lex) source file in a directory,
Automake uses a small program called ylwrap to run yacc (or lex) in a subdirectory. This
is necessary because yacc’s output file name is fixed, and a parallel make could conceivably
invoke more than one instance of yacc simultaneously. The ylwrap program is distributed
with Automake. It should appear in the directory specified by AC_CONFIG_AUX_DIR, or one
of its default locations (see section “Finding ‘configure’ Input” in The Autoconf Manual).
For yacc, simply managing locking is insufficient. The output of yacc always uses the
same symbol names internally, so it isn’t possible to link two yacc parsers into the same
executable.
We recommend using the following renaming hack used in gdb:
#define
#define
#define
#define
#define
#define
#define
#define
#define
#define
#define
#define
#define
#define
#define
#define
#define
#define
#define
#define
#define
#define
#define
#define
#define
#define
#define
#define
#define
#define
#define
#define
#define
#define
#define
yymaxdepth c_maxdepth
yyparse c_parse
yylex
c_lex
yyerror c_error
yylval c_lval
yychar c_char
yydebug c_debug
yypact c_pact
yyr1
c_r1
yyr2
c_r2
yydef
c_def
yychk
c_chk
yypgo
c_pgo
yyact
c_act
yyexca c_exca
yyerrflag c_errflag
yynerrs c_nerrs
yyps
c_ps
yypv
c_pv
yys
c_s
yy_yys c_yys
yystate c_state
yytmp
c_tmp
yyv
c_v
yy_yyv c_yyv
yyval
c_val
yylloc c_lloc
yyreds c_reds
yytoks c_toks
yylhs
c_yylhs
yylen
c_yylen
yydefred c_yydefred
yydgoto c_yydgoto
yysindex c_yysindex
yyrindex c_yyrindex
Chapter 7: Building Programs and Libraries
49
#define yygindex c_yygindex
#define yytable c_yytable
#define yycheck c_yycheck
#define yyname
c_yyname
#define yyrule
c_yyrule
For each define, replace the ‘c_’ prefix with whatever you like. These defines work for
bison, byacc, and traditional yaccs. If you find a parser generator that uses a symbol not
covered here, please report the new name so it can be added to the list.
7.9 C++ Support
Automake includes full support for C++.
Any package including C++ code must define the output variable CXX in ‘configure.ac’;
the simplest way to do this is to use the AC_PROG_CXX macro (see section “Particular Program Checks” in The Autoconf Manual).
A few additional variables are defined when a C++ source file is seen:
CXX
The name of the C++ compiler.
CXXFLAGS
Any flags to pass to the C++ compiler.
AM_CXXFLAGS
The maintainer’s variant of CXXFLAGS.
CXXCOMPILE
The command used to actually compile a C++ source file. The file name is
appended to form the complete command line.
CXXLINK
The command used to actually link a C++ program.
7.10 Assembly Support
Automake includes some support for assembly code.
The variable CCAS holds the name of the compiler used to build assembly code. This
compiler must work a bit like a C compiler; in particular it must accept ‘-c’ and ‘-o’.
The values of CCASFLAGS and AM_CCASFLAGS (or its per-target definition) are passed to the
compilation.
The autoconf macro AM_PROG_AS will define CCAS and CCASFLAGS for you (unless they
are already set, it simply sets CCAS to the C compiler and CCASFLAGS to the C compiler
flags), but you are free to define these variables by other means.
Only the suffixes ‘.s’ and ‘.S’ are recognized by automake as being files containing
assembly code.
7.11 Fortran Support
7.11.1 Overview
Automake includes full support for Fortran. There are two Fortran interfaces within automake, one specific to Fortran 77 (the so-called ‘F77’ interface) and one for all Fortran
dialects (the ‘FC’ interface), which should include Fortran 77. The newer FC interface
Chapter 7: Building Programs and Libraries
50
is preferred, and new code should use this in preference to the older F77 interface. The
description below refers to the FC interface, but makes remarks about the F77 interface
where these seem relevant; for full details, see the Autoconf manual.
Probably the only time you will have to use the F77 interface is when your project uses
both Fortran 77 and Fortran 9x sources and the Fortran 77 code uses features which a
Fortran 9x compiler will typically not support. If you are in this situation, you might have
to be clever about using both interfaces; but in this case you quite probably have a variety
of portability problems anyway.
Any package including Fortran code must define the output variable FC in
‘configure.ac’; the simplest way to do this is to use the AC_PROG_FC macro (see section
“Particular Program Checks” in The Autoconf Manual).
A few additional variables are defined when a Fortran source file is seen:
FC
The name of the Fortran compiler.
FCFLAGS
Any flags to pass to the Fortran compiler.
AM_FCFLAGS
The maintainer’s variant of FCFLAGS.
RFLAGS
Any flags to pass to the Ratfor compiler.
AM_RFLAGS
The maintainer’s variant of RFLAGS.
FCCOMPILE
The command used to actually compile a Fortran source file. The file name is
appended to form the complete command line.
FCLINK
The command used to actually link a pure Fortran program or shared library.
Automake still provides the older Fortran 77 support, using the ‘AC_PROG_F77’ macro,
and the substituted variables ‘F77’, ‘FFLAGS’, ‘AM_FFLAGS’, ‘F77COMPILE’ and ‘FLINK’, instead of the analogous variables described above.
Automake can handle preprocessing Fortran and Ratfor source files in addition to compiling them5 . Automake also contains some support for creating programs and shared libraries
that are a mixture of Fortran and other languages (see Section 7.11.4 [Mixing Fortran With
C and C++], page 52).
Automake has in the past associated the file extension ‘.f’ with the F77 interface.
Though this is preserved at present for the sake of backward compatibility, it is rather
inconsistent with the intention that the FC interface is the preferred one. If you wish to
change this (and we think that you should), then you can do so by defining the environment
variable ‘AUTOMAKE_F_IS_FC’. If this is set equal to ‘1’, then the extension ‘.f’ is associated
with the FC interface; if it is zero or undefined, the extension is associated with the F77
interface; we hope to change the default (the unset case) to FC in future.
5
See also the information on rules in section “Catalogue of Rules” in The GNU Make Manual.
Chapter 7: Building Programs and Libraries
51
7.11.2 Compiling Fortran Files
‘N.o’ is made automatically from ‘N.f’ (or ‘N.F’ or ‘N.r’ by running the Fortran compiler.
The precise command used is as follows:
‘.f’
$(FCCOMPILE) -c -o $ $<
‘.r’
$(RCOMPILE) -c -o $ $<
The compilation commands in turn expand into
$(FCCOMPILE)
$(FC) $(AM_FCFLAGS) $(FCFLAGS)
$(RCOMPILE)
$(FC) $(AM_FCFLAGS) $(FCFLAGS) $(AM_RFLAGS) $(RFLAGS)
This is for the case where ‘.f’ is associated with the FC interface; if ‘.f’ is associated
with the F77 interface, the commands are different but analogous.
The handling of preprocessable Fortran is rather more complicated – see the next section.
7.11.3 Preprocessing Fortran
It is possible to use Fortran which has cpp-style directives within it. Some Fortran compilers,
such as g77, can process these directives internally, and so need no separate preprocessing
stage; in other cases, the code must be compiled indirectly, with a preprocessor producing
pure Fortran code which is only then passed to the compiler.
Because of the syntactical differences in the underlying languages, however it is not
always possible to do this using the cpp program, and you may need help from a separate
Fortran-specific preprocessor.6
Automake’s support for preprocessed Fortran is tightly bound to the Autoconf AC_PROG_
FPP macro (introduced in version XXX), which determines if the Fortran compiler can cope
with preprocessor directives, and if not finds a preprocessor which can. It looks for files
with a ‘.F’ extension (the extension is configurable).
The AC_PROG_FPP macro takes as argument a list of features that you require a preprocessor to support (handling of ‘-I’ and ‘-D’ options, and so on), and does one of two
things:
1. checks whether your Fortran compiler can handle the required set of preprocessor directives internally; and if not
2. checks whether it can find a separate preprocessor which can turn the preprocessable
code into a form which the Fortran compiler can handle.
The first is referred to as ‘direct’ mode, and the second as ‘indirect’ mode. See the
Autoconf documentation of the AC_PROG_FPP macro for more details, but note that the
@FPPDIRECT_TRUE@ and _FALSE variables referred to there are the implementation of an
automake conditional, so that on the (hopefully rare) occasions when you have to handle
something by hand in a ‘Makefile.am’, you can handle both direct and indirect mode using
a construction like:
6
There is no formal standard for Fortran preprocessors, but Sun have produced a preprocessor fpp, which
is available for download at http://www.netlib.org/fortran/; this comes with a free-ish but not quite
open-source licence. The documentation within that distribution is, in effect, a useful specification of a
Fortran preprocessor syntax.
Chapter 7: Building Programs and Libraries
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if FPPDIRECT
## do things appropriate for direct mode
else !FPPDIRECT
## do things appropriate for indirect mode
endif !FPPDIRECT
Handling Ratfor is a type of preprocessing, but this is rather more straightforward. The
file ‘N.f’ is made automatically from ‘N.r’ by a rule which runs just the preprocessor to
convert a Ratfor source file into a strict Fortran 77 source file. The precise command used
is as follows:
‘.r’
$(FC) $(AM_FCFLAGS) $(FCFLAGS) $(AM_RFLAGS) $(RFLAGS)
(or the corresponding alternatives for the F77 interface).
7.11.4 Mixing Fortran With C and C++
Automake currently provides limited support for creating programs and shared libraries that
are a mixture of Fortran and C and/or C++. However, there are many other issues related
to mixing Fortran with other languages that are not (currently) handled by Automake, but
that are handled by other packages7 .
7
For example, the cfortran package addresses all of these inter-language issues, and runs under nearly all
Fortran 77, C and C++ compilers on nearly all platforms. However, cfortran is not yet Free Software,
but it will be in the next major release.
Chapter 7: Building Programs and Libraries
53
Automake can help in two ways:
1. Automatic selection of the linker depending on which combinations of source code.
2. Automatic selection of the appropriate linker flags (e.g., ‘-L’ and ‘-l’) to pass to the
automatically selected linker in order to link in the appropriate Fortran 77 intrinsic
and run-time libraries.
These extra Fortran 77 linker flags are supplied in the output variable FCLIBS by the
AC_FC_LIBRARY_LDFLAGS Autoconf macro supplied with newer versions of Autoconf
(Autoconf version 2.13 and later; substitute FLIBS and AC_F77_LIBRARY_LDFLAGS for
the F77 interface). See section “Fortran Compiler Characteristics” in The Autoconf
Manual.
Chapter 7: Building Programs and Libraries
54
7.11.4.1 How the Linker is Chosen
When a program or library mixes several languages, Automake choose the linker according
to the following priorities. (The names in parentheses are the variables containing the link
command.)
1. Native Java (GCJLINK)
2. C++ (CXXLINK)
3. Fortran (FCLINK)
4. Fortran 77 (F77LINK)
5. Objective C (OBJCLINK)
6. C (LINK)
For example, if Fortran 77, C and C++ source code is compiled into a program, then the
C++ linker will be used. In this case, if the C or Fortran 77 linkers required any special
libraries that weren’t included by the C++ linker, then they must be manually added to an
_LDADD or _LIBADD variable by the user writing the ‘Makefile.am’.
Automake only looks at the file names listed in ‘_SOURCES’ variables to choose the linker,
and defaults to the C linker. Sometimes this is inconvenient because you are linking against
a library written in another language and would like to set the linker more appropriately.
See Section 7.3.5 [Libtool Convenience Libraries], page 37, for a trick with nodist_EXTRA_
..._SOURCES.
7.12 Java Support
Automake includes support for compiled Java, using gcj, the Java front end to the GNU
Compiler Collection.
Any package including Java code to be compiled must define the output variable
GCJ in ‘configure.ac’; the variable GCJFLAGS must also be defined somehow (either in
‘configure.ac’ or ‘Makefile.am’). The simplest way to do this is to use the AM_PROG_GCJ
macro.
By default, programs including Java source files are linked with gcj.
As always, the contents of AM_GCJFLAGS are passed to every compilation invoking gcj
(in its role as an ahead-of-time compiler, when invoking it to create ‘.class’ files, AM_
JAVACFLAGS is used instead). If it is necessary to pass options to gcj from ‘Makefile.am’,
this variable, and not the user variable GCJFLAGS, should be used.
gcj can be used to compile ‘.java’, ‘.class’, ‘.zip’, or ‘.jar’ files.
When linking, gcj requires that the main class be specified using the ‘--main=’ option.
The easiest way to do this is to use the _LDFLAGS variable for the program.
7.13 Support for Other Languages
Automake currently only includes full support for C, C++ (see Section 7.9 [C++ Support],
page 49), Fortran (see Section 7.11 [Fortran Support], page 49), and Java (see Section 7.12
[Java Support], page 54). There is only rudimentary support for other languages, support
for which will be improved based on user demand.
Some limited support for adding your own languages is available via the suffix rule
handling (see Section 17.2 [Suffixes], page 80).
Chapter 7: Building Programs and Libraries
55
7.14 Automatic de-ANSI-fication
Although the GNU standards allow the use of ANSI C, this can have the effect of limiting
portability of a package to some older compilers (notably the SunOS C compiler).
Automake allows you to work around this problem on such machines by de-ANSI-fying
each source file before the actual compilation takes place.
If the ‘Makefile.am’ variable AUTOMAKE_OPTIONS (see Chapter 16 [Options], page 76)
contains the option ‘ansi2knr’ then code to handle de-ANSI-fication is inserted into the
generated ‘Makefile.in’.
This causes each C source file in the directory to be treated as ANSI C. If an ANSI C
compiler is available, it is used. If no ANSI C compiler is available, the ansi2knr program
is used to convert the source files into K&R C, which is then compiled.
The ansi2knr program is simple-minded. It assumes the source code will be formatted
in a particular way; see the ansi2knr man page for details.
Support for de-ANSI-fication requires the source files ‘ansi2knr.c’ and ‘ansi2knr.1’ to
be in the same package as the ANSI C source; these files are distributed with Automake.
Also, the package ‘configure.ac’ must call the macro AM_C_PROTOTYPES (see Section 5.6
[Macros], page 19).
Automake also handles finding the ansi2knr support files in some other directory in the
current package. This is done by prepending the relative path to the appropriate directory
to the ansi2knr option. For instance, suppose the package has ANSI C code in the ‘src’
and ‘lib’ subdirectories. The files ‘ansi2knr.c’ and ‘ansi2knr.1’ appear in ‘lib’. Then
this could appear in ‘src/Makefile.am’:
AUTOMAKE_OPTIONS = ../lib/ansi2knr
If no directory prefix is given, the files are assumed to be in the current directory.
Note that automatic de-ANSI-fication will not work when the package is being built
for a different host architecture. That is because automake currently has no way to build
ansi2knr for the build machine.
Using LIBOBJS with source de-ANSI-fication used to require hand-crafted code in
‘configure’ to append ‘$U’ to basenames in LIBOBJS. This is no longer true today.
Starting with version 2.54, Autoconf takes care of rewriting LIBOBJS and LTLIBOBJS. (see
section “AC_LIBOBJ vs. LIBOBJS” in The Autoconf Manual)
7.15 Automatic dependency tracking
As a developer it is often painful to continually update the ‘Makefile.in’ whenever the
include-file dependencies change in a project. Automake supplies a way to automatically
track dependency changes.
Automake always uses complete dependencies for a compilation, including system headers. Automake’s model is that dependency computation should be a side effect of the build.
To this end, dependencies are computed by running all compilations through a special
wrapper program called depcomp. depcomp understands how to coax many different C and
C++ compilers into generating dependency information in the format it requires. ‘automake
-a’ will install depcomp into your source tree for you. If depcomp can’t figure out how to
properly invoke your compiler, dependency tracking will simply be disabled for your build.
Chapter 8: Other Derived Objects
56
Experience with earlier versions of Automake (see Section 27.2 [Dependency Tracking
Evolution], page 117) taught us that it is not reliable to generate dependencies only on the
maintainer’s system, as configurations vary too much. So instead Automake implements
dependency tracking at build time.
Automatic dependency tracking can be suppressed by putting ‘no-dependencies’ in the
variable AUTOMAKE_OPTIONS, or passing ‘no-dependencies’ as an argument to AM_INIT_
AUTOMAKE (this should be the preferred way). Or, you can invoke automake with the ‘-i’
option. Dependency tracking is enabled by default.
The person building your package also can choose to disable dependency tracking by
configuring with ‘--disable-dependency-tracking’.
7.16 Support for executable extensions
On some platforms, such as Windows, executables are expected to have an extension such as
‘.exe’. On these platforms, some compilers (GCC among them) will automatically generate
‘foo.exe’ when asked to generate ‘foo’.
Automake provides mostly-transparent support for this. Unfortunately mostly doesn’t
yet mean fully. Until the English dictionary is revised, you will have to assist Automake if
your package must support those platforms.
One thing you must be aware of is that, internally, Automake rewrites something like
this:
bin_PROGRAMS = liver
to this:
bin_PROGRAMS = liver$(EXEEXT)
The targets Automake generates are likewise given the ‘$(EXEEXT)’ extension.
However, Automake cannot apply this rewriting to configure substitutions. This means
that if you are conditionally building a program using such a substitution, then your
‘configure.ac’ must take care to add ‘$(EXEEXT)’ when constructing the output variable.
With Autoconf 2.13 and earlier, you must explicitly use AC_EXEEXT to get this support. With Autoconf 2.50, AC_EXEEXT is run automatically if you configure a compiler (say,
through AC_PROG_CC).
Sometimes maintainers like to write an explicit link rule for their program. Without
executable extension support, this is easy—you simply write a rule whose target is the
name of the program. However, when executable extension support is enabled, you must
instead add the ‘$(EXEEXT)’ suffix.
Unfortunately, due to the change in Autoconf 2.50, this means you must always add this
extension. However, this is a problem for maintainers who know their package will never
run on a platform that has executable extensions. For those maintainers, the ‘no-exeext’
option (see Chapter 16 [Options], page 76) will disable this feature. This works in a fairly
ugly way; if ‘no-exeext’ is seen, then the presence of a rule for a target named foo in
‘Makefile.am’ will override an automake-generated rule for ‘foo$(EXEEXT)’. Without the
‘no-exeext’ option, this use will give a diagnostic.
Chapter 8: Other Derived Objects
57
8 Other Derived Objects
Automake can handle derived objects that are not C programs. Sometimes the support for
actually building such objects must be explicitly supplied, but Automake will still automatically handle installation and distribution.
8.1 Executable Scripts
It is possible to define and install programs that are scripts. Such programs are listed using
the SCRIPTS primary name. Automake doesn’t define any dependencies for scripts; the
‘Makefile.am’ should include the appropriate rules.
Automake does not assume that scripts are derived objects; such objects must be deleted
by hand (see Chapter 12 [Clean], page 70).
The automake program itself is a Perl script that is generated from ‘automake.in’. Here
is how this is handled:
bin_SCRIPTS = automake
CLEANFILES = $(bin_SCRIPTS)
do_subst = sed -e ’s,[@]datadir[@],$(datadir),g’ \
-e ’s,[@]PERL[@],$(PERL),g’ \
-e ’s,[@]PACKAGE[@],$(PACKAGE),g’ \
-e ’s,[@]VERSION[@],$(VERSION),g’ \
...
automake: automake.in Makefile
$(do_subst) < $(srcdir)/automake.in > automake
chmod +x automake
Because—as we have just seen—scripts can be built, they are not distributed by default.
Scripts that should be distributed can be specified using a dist_ prefix as in other primaries.
For instance, the following ‘Makefile.am’ declares that ‘my_script’ should be distributed
and installed in ‘$(sbindir)’.
dist_sbin_SCRIPTS = my_script
Script objects can be installed in bindir, sbindir, libexecdir, or pkgdatadir.
Scripts that need not being installed can be listed in noinst_SCRIPTS, and among them,
those which are needed only by ‘make check’ should go in check_SCRIPTS.
8.2 Header files
Header files that must be installed are specified by the HEADERS family of variables. Headers
can be installed in includedir, oldincludedir, pkgincludedir or any other directory you
may have defined (see Section 2.3 [Uniform], page 3). For instance,
include_HEADERS = foo.h bar/bar.h
will install the two files as ‘$(includedir)/foo.h’ and ‘$(includedir)/bar.h’.
The nobase_ prefix is also supported,
Chapter 8: Other Derived Objects
58
nobase_include_HEADERS = foo.h bar/bar.h
will install the two files as ‘$(includedir)/foo.h’ and ‘$(includedir)/bar/bar.h’ (see
Section 6.3 [Alternative], page 28).
Usually, only header files that accompany installed libraries need to be installed. Headers
used by programs or convenience libraries are not installed. The noinst_HEADERS variable
can be used for such headers. However when the header actually belongs to one convenient
library or program, we recommend listing it in the program’s or library’s _SOURCES variable
(see Section 7.1.1 [Program Sources], page 30) instead of in noinst_HEADERS. This is
clearer for the ‘Makefile.am’ reader. noinst_HEADERS would be the right variable to use
in a directory containing only headers and no associated library or program.
All header files must be listed somewhere; in a _SOURCES variable or in a _HEADERS
variable. Missing ones will not appear in the distribution.
For header files that are built and must not be distributed, use the nodist_ prefix
as in nodist_include_HEADERS or nodist_prog_SOURCES. If these generated headers are
needed during the build, you must also ensure they exist before they are used (see Section 8.4
[Sources], page 58).
8.3 Architecture-independent data files
Automake supports the installation of miscellaneous data files using the DATA family of
variables.
Such data can be installed in the directories datadir, sysconfdir, sharedstatedir,
localstatedir, or pkgdatadir.
By default, data files are not included in a distribution. Of course, you can use the
dist_ prefix to change this on a per-variable basis.
Here is how Automake declares its auxiliary data files:
dist_pkgdata_DATA = clean-kr.am clean.am ...
8.4 Built sources
Because Automake’s automatic dependency tracking works as a side-effect of compilation
(see Section 7.15 [Dependencies], page 55) there is a bootstrap issue: a target should not
be compiled before its dependencies are made, but these dependencies are unknown until
the target is first compiled.
Ordinarily this is not a problem, because dependencies are distributed sources: they
preexist and do not need to be built. Suppose that ‘foo.c’ includes ‘foo.h’. When it first
compiles ‘foo.o’, make only knows that ‘foo.o’ depends on ‘foo.c’. As a side-effect of this
compilation depcomp records the ‘foo.h’ dependency so that following invocations of make
will honor it. In these conditions, it’s clear there is no problem: either ‘foo.o’ doesn’t exist
and has to be built (regardless of the dependencies), or accurate dependencies exist and
they can be used to decide whether ‘foo.o’ should be rebuilt.
It’s a different story if ‘foo.h’ doesn’t exist by the first make run. For instance, there
might be a rule to build ‘foo.h’. This time ‘file.o’’s build will fail because the compiler
can’t find ‘foo.h’. make failed to trigger the rule to build ‘foo.h’ first by lack of dependency
information.
Chapter 8: Other Derived Objects
59
The BUILT_SOURCES variable is a workaround for this problem. A source file listed in
BUILT_SOURCES is made on ‘make all’ or ‘make check’ (or even ‘make install’) before
other targets are processed. However, such a source file is not compiled unless explicitly
requested by mentioning it in some other _SOURCES variable.
So, to conclude our introductory example, we could use ‘BUILT_SOURCES = foo.h’ to
ensure ‘foo.h’ gets built before any other target (including ‘foo.o’) during ‘make all’ or
‘make check’.
BUILT_SOURCES is actually a bit of a misnomer, as any file which must be created early
in the build process can be listed in this variable. Moreover, all built sources do not
necessarily have to be listed in BUILT_SOURCES. For instance, a generated ‘.c’ file doesn’t
need to appear in BUILT_SOURCES (unless it is included by another source), because it’s a
known dependency of the associated object.
It might be important to emphasize that BUILT_SOURCES is honored only by ‘make all’,
‘make check’ and ‘make install’. This means you cannot build a specific target (e.g., ‘make
foo’) in a clean tree if it depends on a built source. However it will succeed if you have run
‘make all’ earlier, because accurate dependencies are already available.
The next section illustrates and discusses the handling of built sources on a toy example.
8.4.1 Built sources example
Suppose that ‘foo.c’ includes ‘bindir.h’, which is installation-dependent and not distributed: it needs to be built. Here ‘bindir.h’ defines the preprocessor macro bindir to
the value of the make variable bindir (inherited from ‘configure’).
We suggest several implementations below. It’s not meant to be an exhaustive listing of
all ways to handle built sources, but it will give you a few ideas if you encounter this issue.
First try
This first implementation will illustrate the bootstrap issue mentioned in the previous section (see Section 8.4 [Sources], page 58).
Here is a tentative ‘Makefile.am’.
# This won’t work.
bin_PROGRAMS = foo
foo_SOURCES = foo.c
nodist_foo_SOURCES = bindir.h
CLEANFILES = bindir.h
bindir.h: Makefile
echo ’#define bindir "$(bindir)"’ >$@
This setup doesn’t work, because Automake doesn’t know that ‘foo.c’ includes
‘bindir.h’.
Remember, automatic dependency tracking works as a side-effect of
compilation, so the dependencies of ‘foo.o’ will be known only after ‘foo.o’ has been
compiled (see Section 7.15 [Dependencies], page 55). The symptom is as follows.
% make
source=’foo.c’ object=’foo.o’ libtool=no \
depfile=’.deps/foo.Po’ tmpdepfile=’.deps/foo.TPo’ \
depmode=gcc /bin/sh ./depcomp \
gcc -I. -I. -g -O2 -c ‘test -f ’foo.c’ || echo ’./’‘foo.c
Chapter 8: Other Derived Objects
60
foo.c:2: bindir.h: No such file or directory
make: *** [foo.o] Error 1
In this example ‘bindir.h’ is not distributed, not installed, and it is not even being built
on-time. One may wonder what the ‘nodist_foo_SOURCES = bindir.h’ line has any use at
all. This line simply states that ‘bindir.h’ is a source of foo, so for instance, it should be
inspected while generating tags (see Section 17.1 [Tags], page 79). In other words, it does
not help our present problem, and the build would fail identically without it.
Using BUILT_SOURCES
A solution is to require ‘bindir.h’ to be built before anything else. This is what BUILT_
SOURCES is meant for (see Section 8.4 [Sources], page 58).
bin_PROGRAMS = foo
foo_SOURCES = foo.c
nodist_foo_SOURCES = bindir.h
BUILT_SOURCES = bindir.h
CLEANFILES = bindir.h
bindir.h: Makefile
echo ’#define bindir "$(bindir)"’ >$@
See how ‘bindir.h’ get built first:
% make
echo ’#define bindir "/usr/local/bin"’ >bindir.h
make all-am
make[1]: Entering directory ‘/home/adl/tmp’
source=’foo.c’ object=’foo.o’ libtool=no \
depfile=’.deps/foo.Po’ tmpdepfile=’.deps/foo.TPo’ \
depmode=gcc /bin/sh ./depcomp \
gcc -I. -I. -g -O2 -c ‘test -f ’foo.c’ || echo ’./’‘foo.c
gcc -g -O2
-o foo foo.o
make[1]: Leaving directory ‘/home/adl/tmp’
However, as said earlier, BUILT_SOURCES applies only to the all, check, and install
targets. It still fails if you try to run ‘make foo’ explicitly:
% make clean
test -z "bindir.h" || rm -f bindir.h
test -z "foo" || rm -f foo
rm -f *.o
% : > .deps/foo.Po # Suppress previously recorded dependencies
% make foo
source=’foo.c’ object=’foo.o’ libtool=no \
depfile=’.deps/foo.Po’ tmpdepfile=’.deps/foo.TPo’ \
depmode=gcc /bin/sh ./depcomp \
gcc -I. -I. -g -O2 -c ‘test -f ’foo.c’ || echo ’./’‘foo.c
foo.c:2: bindir.h: No such file or directory
make: *** [foo.o] Error 1
Chapter 8: Other Derived Objects
61
Recording dependencies manually
Usually people are happy enough with BUILT_SOURCES because they never build targets such
as ‘make foo’ before ‘make all’, as in the previous example. However if this matters to you,
you can avoid BUILT_SOURCES and record such dependencies explicitly in the ‘Makefile.am’.
bin_PROGRAMS = foo
foo_SOURCES = foo.c
nodist_foo_SOURCES = bindir.h
foo.$(OBJEXT): bindir.h
CLEANFILES = bindir.h
bindir.h: Makefile
echo ’#define bindir "$(bindir)"’ >$@
You don’t have to list all the dependencies of ‘foo.o’ explicitly, only those that might
need to be built. If a dependency already exists, it will not hinder the first compilation
and will be recorded by the normal dependency tracking code. (Note that after this first
compilation the dependency tracking code will also have recorded the dependency between
‘foo.o’ and ‘bindir.h’; so our explicit dependency is really useful to the first build only.)
Adding explicit dependencies like this can be a bit dangerous if you are not careful
enough. This is due to the way Automake tries not to overwrite your rules (it assumes you
know better than it). ‘foo.$(OBJEXT): bindir.h’ supersedes any rule Automake may want
to output to build ‘foo.$(OBJEXT)’. It happens to work in this case because Automake
doesn’t have to output any ‘foo.$(OBJEXT):’ target: it relies on a suffix rule instead (i.e.,
‘.c.$(OBJEXT):’). Always check the generated ‘Makefile.in’ if you do this.
Build ‘bindir.h’ from ‘configure’
It’s possible to define this preprocessor macro from ‘configure’, either in ‘config.h’ (see
section “Defining Directories” in The Autoconf Manual), or by processing a ‘bindir.h.in’
file using AC_CONFIG_FILES (see section “Configuration Actions” in The Autoconf Manual).
At this point it should be clear that building ‘bindir.h’ from ‘configure’ work well for
this example. ‘bindir.h’ will exist before you build any target, hence will not cause any
dependency issue.
The Makefile can be shrunk as follows. We do not even have to mention ‘bindir.h’.
bin_PROGRAMS = foo
foo_SOURCES = foo.c
However, it’s not always possible to build sources from ‘configure’, especially when
these sources are generated by a tool that needs to be built first...
Build ‘bindir.c’, not ‘bindir.h’.
Another attractive idea is to define bindir as a variable or function exported from
‘bindir.o’, and build ‘bindir.c’ instead of ‘bindir.h’.
noinst_PROGRAMS = foo
foo_SOURCES = foo.c bindir.h
nodist_foo_SOURCES = bindir.c
CLEANFILES = bindir.c
bindir.c: Makefile
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echo ’const char bindir[] = "$(bindir)";’ >$@
‘bindir.h’ contains just the variable’s declaration and doesn’t need to be built, so it
won’t cause any trouble. ‘bindir.o’ is always dependent on ‘bindir.c’, so ‘bindir.c’ will
get built first.
Which is best?
There is no panacea, of course. Each solution has its merits and drawbacks.
You cannot use BUILT_SOURCES if the ability to run ‘make foo’ on a clean tree is important to you.
You won’t add explicit dependencies if you are leery of overriding an Automake rule by
mistake.
Building files from ‘./configure’ is not always possible, neither is converting ‘.h’ files
into ‘.c’ files.
9 Other GNU Tools
Since Automake is primarily intended to generate ‘Makefile.in’s for use in GNU programs,
it tries hard to interoperate with other GNU tools.
9.1 Emacs Lisp
Automake provides some support for Emacs Lisp. The LISP primary is used to hold a
list of ‘.el’ files. Possible prefixes for this primary are lisp_ and noinst_. Note that if
lisp_LISP is defined, then ‘configure.ac’ must run AM_PATH_LISPDIR (see Section 5.6
[Macros], page 19).
Lisp sources are not distributed by default. You can prefix the LISP primary with
dist_, as in dist_lisp_LISP or dist_noinst_LISP, to indicate that these files should be
distributed.
Automake will byte-compile all Emacs Lisp source files using the Emacs found by AM_
PATH_LISPDIR, if any was found.
Byte-compiled Emacs Lisp files are not portable among all versions of Emacs, so it
makes sense to turn this off if you expect sites to have more than one version of Emacs
installed. Furthermore, many packages don’t actually benefit from byte-compilation. Still,
we recommend that you byte-compile your Emacs Lisp sources. It is probably better for
sites with strange setups to cope for themselves than to make the installation less nice for
everybody else.
There are two ways to avoid byte-compiling. Historically, we have recommended the
following construct.
lisp_LISP = file1.el file2.el
ELCFILES =
ELCFILES is an internal Automake variable that normally lists all ‘.elc’ files that must be
byte-compiled. Automake defines ELCFILES automatically from lisp_LISP. Emptying this
variable explicitly prevents byte-compilation to occur.
Since Automake 1.8, we now recommend using lisp_DATA instead. As in
Chapter 9: Other GNU Tools
63
lisp_DATA = file1.el file2.el
Note that these two constructs are not equivalent. _LISP will not install a file if Emacs
is not installed, while _DATA will always install its files.
9.2 Gettext
If AM_GNU_GETTEXT is seen in ‘configure.ac’, then Automake turns on support for GNU
gettext, a message catalog system for internationalization (see section “GNU Gettext” in
GNU gettext utilities).
The gettext support in Automake requires the addition of two subdirectories to the
package, ‘intl’ and ‘po’. Automake insures that these directories exist and are mentioned
in SUBDIRS.
9.3 Libtool
Automake provides support for GNU Libtool (see section “Introduction” in The Libtool
Manual) with the LTLIBRARIES primary. See Section 7.3 [A Shared Library], page 34.
9.4 Java
Automake provides some minimal support for Java compilation with the JAVA primary.
Any ‘.java’ files listed in a _JAVA variable will be compiled with JAVAC at build time.
By default, ‘.java’ files are not included in the distribution, you should use the dist_
prefix to distribute them.
Here is a typical setup for distributing ‘.java’ files and installing the ‘.class’ files
resulting from their compilation.
javadir = $(datadir)/java
dist_java_JAVA = a.java b.java ...
Currently Automake enforces the restriction that only one _JAVA primary can be used in
a given ‘Makefile.am’. The reason for this restriction is that, in general, it isn’t possible to
know which ‘.class’ files were generated from which ‘.java’ files, so it would be impossible
to know which files to install where. For instance, a ‘.java’ file can define multiple classes;
the resulting ‘.class’ file names cannot be predicted without parsing the ‘.java’ file.
There are a few variables that are used when compiling Java sources:
JAVAC
The name of the Java compiler. This defaults to ‘javac’.
JAVACFLAGS
The flags to pass to the compiler. This is considered to be a user variable (see
Section 2.5 [User Variables], page 4).
AM_JAVACFLAGS
More flags to pass to the Java compiler. This, and not JAVACFLAGS, should be
used when it is necessary to put Java compiler flags into ‘Makefile.am’.
JAVAROOT
The value of this variable is passed to the ‘-d’ option to javac. It defaults to
‘$(top_builddir)’.
Chapter 9: Other GNU Tools
64
CLASSPATH_ENV
This variable is an sh expression that is used to set the CLASSPATH environment
variable on the javac command line. (In the future we will probably handle
class path setting differently.)
9.5 Python
Automake provides support for Python compilation with the PYTHON primary.
Any files listed in a _PYTHON variable will be byte-compiled with py-compile at install
time. py-compile actually creates both standard (‘.pyc’) and byte-compiled (‘.pyo’) versions of the source files. Note that because byte-compilation occurs at install time, any
files listed in noinst_PYTHON will not be compiled. Python source files are included in the
distribution by default.
Automake ships with an Autoconf macro called AM_PATH_PYTHON that will determine
some Python-related directory variables (see below). If you have called AM_PATH_PYTHON
from ‘configure.ac’, then you may use the following variables to list you Python
source files in your variables: python_PYTHON, pkgpython_PYTHON, pyexecdir_PYTHON,
pkgpyexecdir_PYTHON, depending where you want your files installed.
AM_PATH_PYTHON ([VERSION ], [ACTION-IF-FOUND ],
[ACTION-IF-NOT-FOUND ])
[Macro]
Search a Python interpreter on the system. This macro takes three optional arguments. The first argument, if present, is the minimum version of Python required
for this package: AM_PATH_PYTHON will skip any Python interpreter that is older
than VERSION. If an interpreter is found and satisfies VERSION, then ACTIONIF-FOUND is run. Otherwise, ACTION-IF-NOT-FOUND is run.
If ACTION-IF-NOT-FOUND is not specified, the default is to abort configure. This
is fine when Python is an absolute requirement for the package. Therefore if Python
>= 2.2 is only optional to the package, AM_PATH_PYTHON could be called as follows.
AM_PATH_PYTHON(2.2,, :)
AM_PATH_PYTHON creates the following output variables based on the Python installation found during configuration.
PYTHON
The name of the Python executable, or ‘:’ if no suitable interpreter could be
found.
Assuming ACTION-IF-NOT-FOUND is used (otherwise ‘./configure’ will
abort if Python is absent), the value of PYTHON can be used to setup a conditional in order to disable the relevant part of a build as follows.
AM_PATH_PYTHON(,, :)
AM_CONDITIONAL([HAVE_PYTHON], [test "$PYTHON" != :])
PYTHON_VERSION
The Python version number, in the form major.minor (e.g., ‘1.5’). This is
currently the value of ‘sys.version[:3]’.
Chapter 10: Building documentation
65
PYTHON_PREFIX
The string ‘${prefix}’. This term may be used in future work that needs the
contents of Python’s ‘sys.prefix’, but general consensus is to always use the
value from configure.
PYTHON_EXEC_PREFIX
The string ‘${exec_prefix}’. This term may be used in future work that needs
the contents of Python’s ‘sys.exec_prefix’, but general consensus is to always
use the value from configure.
PYTHON_PLATFORM
The canonical name used by Python to describe the operating system, as given
by ‘sys.platform’. This value is sometimes needed when building Python
extensions.
pythondir
The directory name for the ‘site-packages’ subdirectory of the standard
Python install tree.
pkgpythondir
This is the directory under pythondir that is named after the package. That
is, it is ‘$(pythondir)/$(PACKAGE)’. It is provided as a convenience.
pyexecdir
This is the directory where Python extension modules (shared libraries) should
be installed.
pkgpyexecdir
This is a convenience variable that is defined as ‘$(pyexecdir)/$(PACKAGE)’.
All these directory variables have values that start with either ‘${prefix}’ or
‘${exec_prefix}’ unexpanded. This works fine in ‘Makefiles’, but it makes these
variables hard to use in ‘configure’. This is mandated by the GNU coding standards, so
that the user can run ‘make prefix=/foo install’. The Autoconf manual has a section
with more details on this topic (see section “Installation Directory Variables” in The
Autoconf Manual). See also Section 26.9 [Hard-Coded Install Paths], page 104.
10 Building documentation
Currently Automake provides support for Texinfo and man pages.
10.1 Texinfo
If the current directory contains Texinfo source, you must declare it with the TEXINFOS
primary. Generally Texinfo files are converted into info, and thus the info_TEXINFOS
variable is most commonly used here. Any Texinfo source file must end in the ‘.texi’,
‘.txi’, or ‘.texinfo’ extension. We recommend ‘.texi’ for new manuals.
Automake generates rules to build ‘.info’, ‘.dvi’, ‘.ps’, ‘.pdf’ and ‘.html’ files from
your Texinfo sources. The ‘.info’ files are built by ‘make all’ and installed by ‘make
install’ (unless you use ‘no-installinfo’, see below). The other files can be built on
request by ‘make dvi’, ‘make ps’, ‘make pdf’ and ‘make html’.
Chapter 10: Building documentation
66
If the ‘.texi’ file @includes ‘version.texi’, then that file will be automatically
generated. The file ‘version.texi’ defines four Texinfo flag you can reference using
@value{EDITION}, @value{VERSION}, @value{UPDATED}, and @value{UPDATED-MONTH}.
EDITION
VERSION
UPDATED
Both of these flags hold the version number of your program. They are kept
separate for clarity.
This holds the date the primary ‘.texi’ file was last modified.
UPDATED-MONTH
This holds the name of the month in which the primary ‘.texi’ file was last
modified.
The ‘version.texi’ support requires the mdate-sh script; this script is supplied with
Automake and automatically included when automake is invoked with the ‘--add-missing’
option.
If you have multiple Texinfo files, and you want to use the ‘version.texi’ feature, then
you have to have a separate version file for each Texinfo file. Automake will treat any include
in a Texinfo file that matches ‘vers*.texi’ just as an automatically generated version file.
Sometimes an info file actually depends on more than one ‘.texi’ file. For instance, in
GNU Hello, ‘hello.texi’ includes the file ‘gpl.texi’. You can tell Automake about these
dependencies using the texi _TEXINFOS variable. Here is how GNU Hello does it:
info_TEXINFOS = hello.texi
hello_TEXINFOS = gpl.texi
By default, Automake requires the file ‘texinfo.tex’ to appear in the same directory
as the Texinfo source (this can be changed using the TEXINFO_TEX variable, see below).
However, if you used AC_CONFIG_AUX_DIR in ‘configure.ac’ (see section “Finding ‘configure’ Input” in The Autoconf Manual), then ‘texinfo.tex’ is looked for there. Automake
supplies ‘texinfo.tex’ if ‘--add-missing’ is given.
The option ‘no-texinfo.tex’ can be used to eliminate the requirement for the file
‘texinfo.tex’. Use of the variable TEXINFO_TEX is preferable, however, because that allows
the dvi, ps, and pdf targets to still work.
Automake generates an install-info rule; some people apparently use this. By default,
info pages are installed by ‘make install’. This can be prevented via the no-installinfo
option.
The following variables are used by the Texinfo build rules.
MAKEINFO
The name of the program invoked to build ‘.info’ files. This variable is defined
by Automake. If the makeinfo program is found on the system then it will be
used by default; otherwise missing will be used instead.
MAKEINFOHTML
The command invoked to build ‘.html’ files.
‘$(MAKEINFO) --html’.
Automake defines this to
MAKEINFOFLAGS
User flags passed to each invocation of ‘$(MAKEINFO)’ and ‘$(MAKEINFOHTML)’.
This user variable (see Section 2.5 [User Variables], page 4) is not expected to
Chapter 10: Building documentation
67
be defined in any ‘Makefile’; it can be used by users to pass extra flags to suit
their needs.
AM_MAKEINFOFLAGS
AM_MAKEINFOHTMLFLAGS
Maintainer flags passed to each makeinfo invocation. Unlike MAKEINFOFLAGS,
these variables are meant to be defined by maintainers in ‘Makefile.am’.
‘$(AM_MAKEINFOFLAGS)’ is passed to makeinfo when building ‘.info’ files;
and ‘$(AM_MAKEINFOHTMLFLAGS)’ is used when building ‘.html’ files.
For instance, the following setting can be used to obtain one single ‘.html’ file
per manual, without node separators.
AM_MAKEINFOHTMLFLAGS = --no-headers --no-split
AM_MAKEINFOHTMLFLAGS defaults to ‘$(AM_MAKEINFOFLAGS)’. This means that
defining AM_MAKEINFOFLAGS without defining AM_MAKEINFOHTMLFLAGS will impact builds of both ‘.info’ and ‘.html’ files.
TEXI2DVI
The name of the command that converts a ‘.texi’ file into a ‘.dvi’ file. This
defaults to ‘texi2dvi’, a script that ships with the Texinfo package.
TEXI2PDF
The name of the command that translates a ‘.texi’ file into a ‘.pdf’ file. This
defaults to ‘$(TEXI2DVI) --pdf --batch’.
DVIPS
The name of the command that build a ‘.ps’ file out of a ‘.dvi’ file. This
defaults to ‘dvips’.
TEXINFO_TEX
If your package has Texinfo files in many directories, you can use the variable
TEXINFO_TEX to tell Automake where to find the canonical ‘texinfo.tex’ for
your package. The value of this variable should be the relative path from the
current ‘Makefile.am’ to ‘texinfo.tex’:
TEXINFO_TEX = ../doc/texinfo.tex
10.2 Man pages
A package can also include man pages (but see the GNU standards on this matter, section
“Man Pages” in The GNU Coding Standards.) Man pages are declared using the MANS
primary. Generally the man_MANS variable is used. Man pages are automatically installed
in the correct subdirectory of mandir, based on the file extension.
File extensions such as ‘.1c’ are handled by looking for the valid part of the extension
and using that to determine the correct subdirectory of mandir. Valid section names are
the digits ‘0’ through ‘9’, and the letters ‘l’ and ‘n’.
Sometimes developers prefer to name a man page something like ‘foo.man’ in the source,
and then rename it to have the correct suffix, for example ‘foo.1’, when installing the
file. Automake also supports this mode. For a valid section named SECTION, there is
a corresponding directory named ‘manSECTION dir’, and a corresponding _MANS variable.
Files listed in such a variable are installed in the indicated section. If the file already has
a valid suffix, then it is installed as-is; otherwise the file suffix is changed to match the
section.
For instance, consider this example:
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68
man1_MANS = rename.man thesame.1 alsothesame.1c
In this case, ‘rename.man’ will be renamed to ‘rename.1’ when installed, but the other
files will keep their names.
By default, man pages are installed by ‘make install’. However, since the GNU project
does not require man pages, many maintainers do not expend effort to keep the man pages
up to date. In these cases, the ‘no-installman’ option will prevent the man pages from
being installed by default. The user can still explicitly install them via ‘make install-man’.
Here is how the man pages are handled in GNU cpio (which includes both Texinfo
documentation and man pages):
man_MANS = cpio.1 mt.1
EXTRA_DIST = $(man_MANS)
Man pages are not currently considered to be source, because it is not uncommon for
man pages to be automatically generated. Therefore they are not automatically included
in the distribution. However, this can be changed by use of the dist_ prefix.
The nobase_ prefix is meaningless for man pages and is disallowed.
11 What Gets Installed
11.1 Basics of installation
Naturally, Automake handles the details of actually installing your program once it has been
built. All files named by the various primaries are automatically installed in the appropriate
places when the user runs ‘make install’.
A file named in a primary is installed by copying the built file into the appropriate
directory. The base name of the file is used when installing.
bin_PROGRAMS = hello subdir/goodbye
In this example, both ‘hello’ and ‘goodbye’ will be installed in ‘$(bindir)’.
Sometimes it is useful to avoid the basename step at install time. For instance, you
might have a number of header files in subdirectories of the source tree that are laid out
precisely how you want to install them. In this situation you can use the nobase_ prefix to
suppress the base name step. For example:
nobase_include_HEADERS = stdio.h sys/types.h
Will install ‘stdio.h’ in ‘$(includedir)’ and ‘types.h’ in ‘$(includedir)/sys’.
11.2 The two parts of install
Automake generates separate install-data and install-exec rules, in case the installer
is installing on multiple machines that share directory structure—these targets allow the
machine-independent parts to be installed only once. install-exec installs platformdependent files, and install-data installs platform-independent files. The install target
depends on both of these targets. While Automake tries to automatically segregate objects
into the correct category, the ‘Makefile.am’ author is, in the end, responsible for making
sure this is done correctly.
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Variables using the standard directory prefixes ‘data’, ‘info’, ‘man’, ‘include’,
‘oldinclude’, ‘pkgdata’, or ‘pkginclude’ are installed by install-data.
Variables using the standard directory prefixes ‘bin’, ‘sbin’, ‘libexec’, ‘sysconf’,
‘localstate’, ‘lib’, or ‘pkglib’ are installed by install-exec.
For instance, data_DATA files are installed by install-data, while bin_PROGRAMS files
are installed by install-exec.
Any variable using a user-defined directory prefix with ‘exec’ in the name (e.g.,
myexecbin_PROGRAMS) is installed by install-exec. All other user-defined prefixes are
installed by install-data.
11.3 Extending installation
It is possible to extend this mechanism by defining an install-exec-local or installdata-local rule. If these rules exist, they will be run at ‘make install’ time. These rules
can do almost anything; care is required.
Automake also supports two install hooks, install-exec-hook and install-datahook. These hooks are run after all other install rules of the appropriate type, exec or data,
have completed. So, for instance, it is possible to perform post-installation modifications
using an install hook. Section 22.1 [Extending], page 84 gives some examples.
11.4 Staged installs
Automake generates support for the DESTDIR variable in all install rules. DESTDIR is used
during the ‘make install’ step to relocate install objects into a staging area. Each object
and path is prefixed with the value of DESTDIR before being copied into the install area.
Here is an example of typical DESTDIR usage:
mkdir /tmp/staging &&
make DESTDIR=/tmp/staging install
The mkdir command avoids a security problem if the attacker creates a symbolic link
from ‘/tmp/staging’ to a victim area; then make places install objects in a directory
tree built under ‘/tmp/staging’. If ‘/gnu/bin/foo’ and ‘/gnu/share/aclocal/foo.m4’
are to be installed, the above command would install ‘/tmp/staging/gnu/bin/foo’ and
‘/tmp/staging/gnu/share/aclocal/foo.m4’.
This feature is commonly used to build install images and packages. For more information, see section “Makefile Conventions” in The GNU Coding Standards.
Support for DESTDIR is implemented by coding it directly into the install rules. If your
‘Makefile.am’ uses a local install rule (e.g., install-exec-local) or an install hook, then
you must write that code to respect DESTDIR.
11.5 Rules for the user
Automake also generates rules for targets uninstall, installdirs, and install-strip.
Automake supports uninstall-local and uninstall-hook. There is no notion of separate uninstalls for “exec” and “data”, as these features would not provide additional functionality.
Note that uninstall is not meant as a replacement for a real packaging tool.
Chapter 13: What Goes in a Distribution
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12 What Gets Cleaned
The GNU Makefile Standards specify a number of different clean rules. See section “Standard Targets for Users” in The GNU Coding Standards.
Generally the files that can be cleaned are determined automatically by Automake. Of
course, Automake also recognizes some variables that can be defined to specify additional
files to clean. These variables are MOSTLYCLEANFILES, CLEANFILES, DISTCLEANFILES, and
MAINTAINERCLEANFILES.
When cleaning involves more than deleting some hard-coded list of files, it is also possible
to supplement the cleaning rules with your own commands. Simply define a rule for any of
the mostlyclean-local, clean-local, distclean-local, or maintainer-clean-local
targets (see Section 22.1 [Extending], page 84). A common case is deleting a directory, for
instance, a directory created by the test suite:
clean-local:
-rm -rf testSubDir
As the GNU Standards aren’t always explicit as to which files should be removed by
which rule, we’ve adopted a heuristic that we believe was first formulated by François
Pinard:
• If make built it, and it is commonly something that one would want to rebuild (for
instance, a ‘.o’ file), then mostlyclean should delete it.
• Otherwise, if make built it, then clean should delete it.
• If configure built it, then distclean should delete it.
• If the maintainer built it (for instance, a ‘.info’ file), then maintainer-clean should
delete it. However maintainer-clean should not delete anything that needs to exist
in order to run ‘./configure && make’.
We recommend that you follow this same set of heuristics in your ‘Makefile.am’.
13 What Goes in a Distribution
13.1 Basics of distribution
The dist rule in the generated ‘Makefile.in’ can be used to generate a gzip’d tar file
and other flavors of archive for distribution. The files is named based on the PACKAGE and
VERSION variables defined by AM_INIT_AUTOMAKE (see Section 5.6 [Macros], page 19); more
precisely the gzip’d tar file is named ‘package-version.tar.gz’. You can use the make
variable GZIP_ENV to control how gzip is run. The default setting is ‘--best’.
For the most part, the files to distribute are automatically found by Automake: all
source files are automatically included in a distribution, as are all ‘Makefile.am’s and
‘Makefile.in’s. Automake also has a built-in list of commonly used files that are automatically included if they are found in the current directory (either physically, or as the target
of a ‘Makefile.am’ rule). This list is printed by ‘automake --help’. Also, files that are
read by configure (i.e. the source files corresponding to the files specified in various Autoconf macros such as AC_CONFIG_FILES and siblings) are automatically distributed. Files
Chapter 13: What Goes in a Distribution
71
included in ‘Makefile.am’s (using include) or in ‘configure.ac’ (using m4_include), and
helper scripts installed with ‘automake --add-missing’ are also distributed.
Still, sometimes there are files that must be distributed, but which are not covered in the
automatic rules. These files should be listed in the EXTRA_DIST variable. You can mention
files from subdirectories in EXTRA_DIST.
You can also mention a directory in EXTRA_DIST; in this case the entire directory will be
recursively copied into the distribution. Please note that this will also copy everything in
the directory, including CVS/RCS version control files. We recommend against using this
feature.
If you define SUBDIRS, Automake will recursively include the subdirectories in the distribution. If SUBDIRS is defined conditionally (see Chapter 19 [Conditionals], page 81),
Automake will normally include all directories that could possibly appear in SUBDIRS in
the distribution. If you need to specify the set of directories conditionally, you can set the
variable DIST_SUBDIRS to the exact list of subdirectories to include in the distribution (see
Section 6.2 [Conditional Subdirectories], page 25).
13.2 Fine-grained distribution control
Sometimes you need tighter control over what does not go into the distribution; for instance,
you might have source files that are generated and that you do not want to distribute. In
this case Automake gives fine-grained control using the dist and nodist prefixes. Any
primary or _SOURCES variable can be prefixed with dist_ to add the listed files to the
distribution. Similarly, nodist_ can be used to omit the files from the distribution.
As an example, here is how you would cause some data to be distributed while leaving
some source code out of the distribution:
dist_data_DATA = distribute-this
bin_PROGRAMS = foo
nodist_foo_SOURCES = do-not-distribute.c
13.3 The dist hook
Occasionally it is useful to be able to change the distribution before it is packaged up. If the
dist-hook rule exists, it is run after the distribution directory is filled, but before the actual
tar (or shar) file is created. One way to use this is for distributing files in subdirectories for
which a new ‘Makefile.am’ is overkill:
dist-hook:
mkdir $(distdir)/random
cp -p $(srcdir)/random/a1 $(srcdir)/random/a2 $(distdir)/random
Another way to to use this is for removing unnecessary files that get recursively included
by specifying a directory in EXTRA DIST:
EXTRA_DIST = doc
dist-hook:
rm -rf ‘find $(distdir)/doc -name CVS‘
Two variables that come handy when writing dist-hook rules are ‘$(distdir)’ and
‘$(top_distdir)’.
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‘$(distdir)’ points to the directory where the dist rule will copy files from the current
directory before creating the tarball. If you are at the top-level directory, then ‘distdir
= $(PACKAGE)-$(VERSION)’. When used from subdirectory named ‘foo/’, then ‘distdir
= ../$(PACKAGE)-$(VERSION)/foo’. ‘$(distdir)’ can be a relative or absolute path, do
not assume any form.
‘$(top_distdir)’ always points to the root directory of the distributed tree. At
the top-level it’s equal to ‘$(distdir)’. In the ‘foo/’ subdirectory ‘top_distdir =
../$(PACKAGE)-$(VERSION)’. ‘$(top_distdir)’ too can be a relative or absolute path.
Note that when packages are nested using AC_CONFIG_SUBDIRS (see Section 6.4 [Subpackages], page 29), then ‘$(distdir)’ and ‘$(top_distdir)’ are relative to the package
where ‘make dist’ was run, not to any sub-packages involved.
13.4 Checking the distribution
Automake also generates a distcheck rule that can be of help to ensure that a given
distribution will actually work. distcheck makes a distribution, then tries to do a VPATH
build, run the test suite, and finally make another tarfile to ensure the distribution is selfcontained.
Building the package involves running ‘./configure’. If you need to supply additional
flags to configure, define them in the DISTCHECK_CONFIGURE_FLAGS variable, either in
your top-level ‘Makefile.am’, or on the command line when invoking make.
If the distcheck-hook rule is defined in your top-level ‘Makefile.am’, then it will be
invoked by distcheck after the new distribution has been unpacked, but before the unpacked copy is configured and built. Your distcheck-hook can do almost anything, though
as always caution is advised. Generally this hook is used to check for potential distribution errors not caught by the standard mechanism. Note that distcheck-hook as well
as DISTCHECK_CONFIGURE_FLAGS are not honored in a subpackage ‘Makefile.am’, but the
DISTCHECK_CONFIGURE_FLAGS are passed down to the configure script of the subpackage.
Speaking of potential distribution errors, distcheck also ensures that the distclean
rule actually removes all built files. This is done by running ‘make distcleancheck’ at the
end of the VPATH build. By default, distcleancheck will run distclean and then make
sure the build tree has been emptied by running ‘$(distcleancheck_listfiles)’. Usually
this check will find generated files that you forgot to add to the DISTCLEANFILES variable
(see Chapter 12 [Clean], page 70).
The distcleancheck behavior should be OK for most packages, otherwise you have
the possibility to override the definition of either the distcleancheck rule, or the
‘$(distcleancheck_listfiles)’ variable. For instance, to disable distcleancheck
completely, add the following rule to your top-level ‘Makefile.am’:
distcleancheck:
@:
If you want distcleancheck to ignore built files that have not been cleaned because
they are also part of the distribution, add the following definition instead:
distcleancheck_listfiles = \
find -type f -exec sh -c ’test -f $(srcdir)/{} || echo {}’ ’;’
Chapter 14: Support for test suites
73
The above definition is not the default because it’s usually an error if your Makefiles
cause some distributed files to be rebuilt when the user build the package. (Think about
the user missing the tool required to build the file; or if the required tool is built by your
package, consider the cross-compilation case where it can’t be run.) There is a FAQ entry
about this (see Section 26.4 [distcleancheck], page 94), make sure you read it before playing
with distcleancheck_listfiles.
distcheck also checks that the uninstall rule works properly, both for ordinary and
DESTDIR builds. It does this by invoking ‘make uninstall’, and then it checks the install
tree to see if any files are left over. This check will make sure that you correctly coded your
uninstall-related rules.
By default, the checking is done by the distuninstallcheck rule, and the list of files
in the install tree is generated by ‘$(distuninstallcheck_listfiles’) (this is a variable
whose value is a shell command to run that prints the list of files to stdout).
Either of these can be overridden to modify the behavior of distcheck. For instance,
to disable this check completely, you would write:
distuninstallcheck:
@:
13.5 The types of distributions
Automake generates rules to provide archives of the project for distributions in various
formats. Their targets are:
dist-bzip2
Generate a bzip2 tar archive of the distribution. bzip2 archives are frequently
smaller than gzipped archives.
dist-gzip
Generate a gzip tar archive of the distribution.
dist-shar
Generate a shar archive of the distribution.
dist-zip
Generate a zip archive of the distribution.
dist-tarZ
Generate a compressed tar archive of the distribution.
The rule dist (and its historical synonym dist-all) will create archives in all the
enabled formats, Chapter 16 [Options], page 76. By default, only the dist-gzip target is
hooked to dist.
14 Support for test suites
Automake supports two forms of test suites.
Chapter 14: Support for test suites
74
14.1 Simple Tests
If the variable TESTS is defined, its value is taken to be a list of programs to run in order to
do the testing. The programs can either be derived objects or source objects; the generated
rule will look both in srcdir and ‘.’. Programs needing data files should look for them in
srcdir (which is both an environment variable and a make variable) so they work when
building in a separate directory (see section “Build Directories ” in The Autoconf Manual),
and in particular for the distcheck rule (see Chapter 13 [Dist], page 70).
The number of failures will be printed at the end of the run. If a given test program
exits with a status of 77, then its result is ignored in the final count. This feature allows
non-portable tests to be ignored in environments where they don’t make sense.
The variable TESTS_ENVIRONMENT can be used to set environment variables for the test
run; the environment variable srcdir is set in the rule. If all your test programs are scripts,
you can also set TESTS_ENVIRONMENT to an invocation of the shell (e.g. ‘$(SHELL) -x’); this
can be useful for debugging the tests.
You may define the variable XFAIL_TESTS to a list of tests (usually a subset of TESTS)
that are expected to fail. This will reverse the result of those tests.
Automake ensures that each program listed in TESTS is built before any tests are run;
you can list both source and derived programs in TESTS. For instance, you might want
to run a C program as a test. To do this you would list its name in TESTS and also in
check_PROGRAMS, and then specify it as you would any other program.
14.2 DejaGnu Tests
If dejagnu appears in AUTOMAKE_OPTIONS, then a dejagnu-based test suite is assumed. The
variable DEJATOOL is a list of names that are passed, one at a time, as the ‘--tool’ argument
to runtest invocations; it defaults to the name of the package.
The variable RUNTESTDEFAULTFLAGS holds the ‘--tool’ and ‘--srcdir’ flags that are
passed to dejagnu by default; this can be overridden if necessary.
The variables EXPECT and RUNTEST can also be overridden to provide project-specific
values. For instance, you will need to do this if you are testing a compiler toolchain,
because the default values do not take into account host and target names.
The contents of the variable RUNTESTFLAGS are passed to the runtest invocation. This
is considered a “user variable” (see Section 2.5 [User Variables], page 4). If you need to set
runtest flags in ‘Makefile.am’, you can use AM_RUNTESTFLAGS instead.
Automake will generate rules to create a local ‘site.exp’ file, defining various variables
detected by configure. This file is automatically read by DejaGnu. It is OK for the user
of a package to edit this file in order to tune the test suite. However this is not the place
where the test suite author should define new variables: this should be done elsewhere in
the real test suite code. Especially, ‘site.exp’ should not be distributed.
For more information regarding DejaGnu test suites, see section “Top” in The DejaGnu
Manual.
In either case, the testing is done via ‘make check’.
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75
14.3 Install Tests
The installcheck target is available to the user as a way to run any tests after the package
has been installed. You can add tests to this by writing an installcheck-local rule.
15 Rebuilding Makefiles
Automake generates rules to automatically rebuild ‘Makefile’s, ‘configure’, and other
derived files like ‘Makefile.in’.
If you are using AM_MAINTAINER_MODE in ‘configure.ac’, then these automatic rebuilding rules are only enabled in maintainer mode.
Sometimes you need to run aclocal with an argument like ‘-I’ to tell it where to find
‘.m4’ files. Since sometimes make will automatically run aclocal, you need a way to specify
these arguments. You can do this by defining ACLOCAL_AMFLAGS; this holds arguments that
are passed verbatim to aclocal. This variable is only useful in the top-level ‘Makefile.am’.
Sometimes it is convenient to supplement the rebuild rules for ‘configure’ or
‘config.status’ with additional dependencies. The variables CONFIGURE_DEPENDENCIES
and CONFIG_STATUS_DEPENDENCIES can be used to list these extra dependencies. These
variable should be defined in all ‘Makefile’s of the tree (because these two rebuild rules
are output in all them), so it is safer and easier to AC_SUBST them from ‘configure.ac’.
For instance, the following statement will cause ‘configure’ to be rerun each time
‘version.sh’ is changed.
AC_SUBST([CONFIG_STATUS_DEPENDENCIES], [’$(top_srcdir)/version.sh’])
Note the ‘$(top_srcdir)/’ in the file name. Since this variable is to be used in all
‘Makefile’s, its value must be sensible at any level in the build hierarchy.
Beware not to mistake CONFIGURE_DEPENDENCIES for CONFIG_STATUS_DEPENDENCIES.
CONFIGURE_DEPENDENCIES adds dependencies to the ‘configure’ rule, whose effect is
to run autoconf. This variable should be seldom used, because automake already tracks
m4_included files. However it can be useful when playing tricky games with m4_esyscmd
or similar non-recommendable macros with side effects.
CONFIG_STATUS_DEPENDENCIES adds dependencies to the ‘config.status’ rule, whose
effect is to run ‘configure’. This variable should therefore carry any non-standard source
that may be read as a side effect of running configure, like ‘version.sh’ in the example
above.
Speaking of ‘version.sh’ scripts, we recommend against them today. They are mainly
used when the version of a package is updated automatically by a script (e.g., in daily
builds). Here is what some old-style ‘configure.ac’s may look like:
AC_INIT
. $srcdir/version.sh
AM_INIT_AUTOMAKE([name], $VERSION_NUMBER)
...
Here, ‘version.sh’ is a shell fragment that sets VERSION_NUMBER. The problem with this example is that automake cannot track dependencies (listing ‘version.sh’ in CONFIG_STATUS_
DEPENDENCIES, and distributing this file is up to the user), and that it uses the obsolete
Chapter 16: Changing Automake’s Behavior
76
form of AC_INIT and AM_INIT_AUTOMAKE. Upgrading to the new syntax is not straightforward, because shell variables are not allowed in AC_INIT’s arguments. We recommend that
‘version.sh’ be replaced by an M4 file that is included by ‘configure.ac’:
m4_include([version.m4])
AC_INIT([name], VERSION_NUMBER)
AM_INIT_AUTOMAKE
...
Here ‘version.m4’ could contain something like ‘m4_define([VERSION_NUMBER], [1.2])’.
The advantage of this second form is that automake will take care of the dependencies when
defining the rebuild rule, and will also distribute the file automatically. An inconvenience
is that autoconf will now be rerun each time the version number is bumped, when only
‘configure’ had to be rerun in the previous setup.
16 Changing Automake’s Behavior
Various features of Automake can be controlled by options in the ‘Makefile.am’. Such
options are applied on a per-‘Makefile’ basis when listed in a special ‘Makefile’ variable
named AUTOMAKE_OPTIONS. They are applied globally to all processed ‘Makefiles’ when
listed in the first argument of AM_INIT_AUTOMAKE in ‘configure.ac’. Currently understood
options are:
‘gnits’
‘gnu’
‘foreign’
‘cygnus’
Set the strictness as appropriate. The ‘gnits’ option also implies options
‘readme-alpha’ and ‘check-news’.
‘ansi2knr’
‘path /ansi2knr’
Turn on automatic de-ANSI-fication. See Section 7.14 [ANSI], page 55. If
preceded by a path, the generated ‘Makefile.in’ will look in the specified
directory to find the ‘ansi2knr’ program. The path should be a relative path
to another directory in the same distribution (Automake currently does not
check this).
‘check-news’
Cause ‘make dist’ to fail unless the current version number appears in the first
few lines of the ‘NEWS’ file.
‘dejagnu’
Cause dejagnu-specific rules to be generated. See Chapter 14 [Tests], page 73.
‘dist-bzip2’
Hook dist-bzip2 to dist.
‘dist-shar’
Hook dist-shar to dist.
‘dist-zip’
Hook dist-zip to dist.
Chapter 16: Changing Automake’s Behavior
77
‘dist-tarZ’
Hook dist-tarZ to dist.
‘filename-length-max=99’
Abort if file names longer than 99 characters are found during ‘make dist’.
Such long file names are generally considered not to be portable in tarballs.
See the ‘tar-v7’ and ‘tar-ustar’ options below. This option should be used
in the top-level ‘Makefile.am’ or as an argument of AM_INIT_AUTOMAKE in
‘configure.ac’, it will be ignored otherwise.
‘no-define’
This options is meaningful only when passed as an argument to AM_INIT_
AUTOMAKE. It will prevent the PACKAGE and VERSION variables to be AC_DEFINEd.
‘no-dependencies’
This is similar to using ‘--include-deps’ on the command line, but is useful
for those situations where you don’t have the necessary bits to make automatic
dependency tracking work (see Section 7.15 [Dependencies], page 55). In this
case the effect is to effectively disable automatic dependency tracking.
‘no-dist’
Don’t emit any code related to dist target. This is useful when a package has
its own method for making distributions.
‘no-dist-gzip’
Do not hook dist-gzip to dist.
‘no-exeext’
If your ‘Makefile.am’ defines a rule for target foo, it will override a rule for a
target named ‘foo$(EXEEXT)’. This is necessary when EXEEXT is found to be
empty. However, by default automake will generate an error for this use. The
‘no-exeext’ option will disable this error. This is intended for use only where
it is known in advance that the package will not be ported to Windows, or any
other operating system using extensions on executables.
‘no-installinfo’
The generated ‘Makefile.in’ will not cause info pages to be built or installed
by default. However, info and install-info targets will still be available.
This option is disallowed at ‘gnu’ strictness and above.
‘no-installman’
The generated ‘Makefile.in’ will not cause man pages to be installed by default. However, an install-man target will still be available for optional installation. This option is disallowed at ‘gnu’ strictness and above.
‘nostdinc’
This option can be used to disable the standard ‘-I’ options that are ordinarily
automatically provided by Automake.
‘no-texinfo.tex’
Don’t require ‘texinfo.tex’, even if there are texinfo files in this directory.
‘readme-alpha’
If this release is an alpha release, and the file ‘README-alpha’ exists, then it
will be added to the distribution. If this option is given, version numbers are
Chapter 16: Changing Automake’s Behavior
78
expected to follow one of two forms. The first form is ‘MAJOR.MINOR.ALPHA ’,
where each element is a number; the final period and number should be left off
for non-alpha releases. The second form is ‘MAJOR.MINOR ALPHA ’, where ALPHA
is a letter; it should be omitted for non-alpha releases.
‘std-options’
Make the installcheck rule check that installed scripts and programs support
the ‘--help’ and ‘--version’ options. This also provides a basic check that
the program’s run-time dependencies are satisfied after installation.
In a few situations, programs (or scripts) have to be exempted from this test.
For instance, false (from GNU sh-utils) is never successful, even for ‘--help’
or ‘--version’. You can list such programs in the variable AM_INSTALLCHECK_
STD_OPTIONS_EXEMPT. Programs (not scripts) listed in this variable should be
suffixed by ‘$(EXEEXT)’ for the sake of Win32 or OS/2. For instance, suppose
we build ‘false’ as a program but ‘true.sh’ as a script, and that neither of
them support ‘--help’ or ‘--version’:
AUTOMAKE_OPTIONS = std-options
bin_PROGRAMS = false ...
bin_SCRIPTS = true.sh ...
AM_INSTALLCHECK_STD_OPTIONS_EXEMPT = false$(EXEEXT) true.sh
‘subdir-objects’
If this option is specified, then objects are placed into the subdirectory of the
build directory corresponding to the subdirectory of the source file. For instance, if the source file is ‘subdir/file.cxx’, then the output file would be
‘subdir/file.o’.
‘tar-v7’
‘tar-ustar’
‘tar-pax’
These three mutually exclusive options select the tar format to use when generating tarballs with ‘make dist’. (The tar file created is then compressed
according to the set of ‘no-dist-gzip’, ‘dist-bzip2’ and ‘dist-tarZ’ options
in use.)
These options must be passed as argument to AM_INIT_AUTOMAKE (see Section 5.6 [Macros], page 19) because they can require additional configure checks.
Automake will complain if it sees such options in an AUTOMAKE_OPTIONS variable.
‘tar-v7’ selects the old V7 tar format. This is the historical default. This antiquated format is understood by all tar implementations and supports file names
with up to 99 characters. When given longer file names some tar implementations will diagnose the problem while other will generate broken tarballs or use
non-portable extensions. Furthermore, the V7 format cannot store empty directories. When using this format, consider using the ‘filename-length-max=99’
option to catch file names too long.
‘tar-ustar’ selects the ustar format defined by POSIX 1003.1-1988. This format is believed to be old enough to be portable. It fully supports empty directories. It can store file names with up to 256 characters, provided that the
Chapter 17: Miscellaneous Rules
79
file name can be split at directory separator in two parts, first of them being at
most 155 bytes long. So, in most cases the maximum file name length will be
shorter than 256 characters. However you may run against broken tar implementations that incorrectly handle file names longer than 99 characters (please
report them to bug-automake@gnu.org so we can document this accurately).
‘tar-pax’ selects the new pax interchange format defined by POSIX 1003.12001. It does not limit the length of file names. However, this format is very
young and should probably be restricted to packages that target only very
modern platforms. There are moves to change the pax format in an upwardcompatible way, so this option may refer to a more recent version in the future.
See section “Controlling the Archive Format” in GNU Tar, for further discussion about tar formats.
configure knows several ways to construct these formats. It will not abort if
it cannot find a tool up to the task (so that the package can still be built), but
‘make dist’ will fail.
version
A version number (e.g., ‘0.30’) can be specified. If Automake is not newer than
the version specified, creation of the ‘Makefile.in’ will be suppressed.
‘-Wcategory ’ or ‘--warnings=category ’
These options behave exactly like their command-line counterpart (see Chapter 4 [Invoking Automake], page 10). This allows you to enable or disable some
warning categories on a per-file basis. You can also setup some warnings for
your entire project; for instance, try ‘AM_INIT_AUTOMAKE([-Wall])’ in your
‘configure.ac’.
Unrecognized options are diagnosed by automake.
If you want an option to apply to all the files in the tree, you can use the AM_INIT_
AUTOMAKE macro in ‘configure.ac’. See Section 5.6 [Macros], page 19.
17 Miscellaneous Rules
There are a few rules and variables that didn’t fit anywhere else.
17.1 Interfacing to etags
Automake will generate rules to generate ‘TAGS’ files for use with GNU Emacs under some
circumstances.
If any C, C++ or Fortran 77 source code or headers are present, then tags and TAGS
rules will be generated for the directory. All files listed using the _SOURCES, _HEADERS, and
_LISP primaries will be used to generate tags. Note that generated source files that are not
distributed must be declared in variables like nodist_noinst_HEADERS or nodist_prog _
SOURCES or they will be ignored.
A tags rule will be output at the topmost directory of a multi-directory package. When
run from this topmost directory, ‘make tags’ will generate a ‘TAGS’ file that includes by
reference all ‘TAGS’ files from subdirectories.
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The tags rule will also be generated if the variable ETAGS_ARGS is defined. This variable
is intended for use in directories that contain taggable source that etags does not understand. The user can use the ETAGSFLAGS to pass additional flags to etags; AM_ETAGSFLAGS
is also available for use in ‘Makefile.am’.
Here is how Automake generates tags for its source, and for nodes in its Texinfo file:
ETAGS_ARGS = automake.in --lang=none \
--regex=’/^@node[ \t]+\([^,]+\)/\1/’ automake.texi
If you add file names to ETAGS_ARGS, you will probably also want to define TAGS_
DEPENDENCIES. The contents of this variable are added directly to the dependencies for
the tags rule.
Automake also generates a ctags rule that can be used to build vi-style ‘tags’ files.
The variable CTAGS is the name of the program to invoke (by default ctags); CTAGSFLAGS
can be used by the user to pass additional flags, and AM_CTAGSFLAGS can be used by the
‘Makefile.am’.
Automake will also generate an ID rule that will run mkid on the source. This is only
supported on a directory-by-directory basis.
Finally, Automake also emit rules to support the GNU Global Tags program. The
GTAGS rule runs Global Tags and puts the result in the top build directory. The variable
GTAGS_ARGS holds arguments that are passed to gtags.
17.2 Handling new file extensions
It is sometimes useful to introduce a new implicit rule to handle a file type that Automake
does not know about.
For instance, suppose you had a compiler that could compile ‘.foo’ files to ‘.o’ files.
You would simply define an suffix rule for your language:
.foo.o:
foocc -c -o $@ $<
Then you could directly use a ‘.foo’ file in a _SOURCES variable and expect the correct
results:
bin_PROGRAMS = doit
doit_SOURCES = doit.foo
This was the simpler and more common case. In other cases, you will have to help
Automake to figure which extensions you are defining your suffix rule for. This usually
happens when your extensions does not start with a dot. Then, all you have to do is to put
a list of new suffixes in the SUFFIXES variable before you define your implicit rule.
For instance, the following definition prevents Automake to misinterpret ‘.idlC.cpp:’
as an attempt to transform ‘.idlC’ files into ‘.cpp’ files.
SUFFIXES = .idl C.cpp
.idlC.cpp:
# whatever
As you may have noted, the SUFFIXES variable behaves like the .SUFFIXES special target
of make. You should not touch .SUFFIXES yourself, but use SUFFIXES instead and let
Automake generate the suffix list for .SUFFIXES. Any given SUFFIXES go at the start of
the generated suffixes list, followed by Automake generated suffixes not already in the list.
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81
17.3 Support for Multilibs
Automake has support for an obscure feature called multilibs. A multilib is a library that
is built for multiple different ABIs at a single time; each time the library is built with a
different target flag combination. This is only useful when the library is intended to be
cross-compiled, and it is almost exclusively used for compiler support libraries.
The multilib support is still experimental. Only use it if you are familiar with multilibs
and can debug problems you might encounter.
18 Include
Automake supports an include directive that can be used to include other ‘Makefile’
fragments when automake is run. Note that these fragments are read and interpreted by
automake, not by make. As with conditionals, make has no idea that include is in use.
There are two forms of include:
include $(srcdir)/file
Include a fragment that is found relative to the current source directory.
include $(top_srcdir)/file
Include a fragment that is found relative to the top source directory.
Note that if a fragment is included inside a conditional, then the condition applies to
the entire contents of that fragment.
Makefile fragments included this way are always distributed because they are needed to
rebuild ‘Makefile.in’.
19 Conditionals
Automake supports a simple type of conditionals.
Before using a conditional, you must define it by using AM_CONDITIONAL in the
‘configure.ac’ file (see Section 5.6 [Macros], page 19).
AM_CONDITIONAL (conditional, condition )
[Macro]
The conditional name, conditional, should be a simple string starting with a letter
and containing only letters, digits, and underscores. It must be different from ‘TRUE’
and ‘FALSE’ that are reserved by Automake.
The shell condition (suitable for use in a shell if statement) is evaluated when
configure is run. Note that you must arrange for every AM_CONDITIONAL to be
invoked every time configure is run. If AM_CONDITIONAL is run conditionally (e.g.,
in a shell if statement), then the result will confuse automake.
Conditionals typically depend upon options that the user provides to the configure
script. Here is an example of how to write a conditional that is true if the user uses the
‘--enable-debug’ option.
Chapter 20: The effect of ‘--gnu’ and ‘--gnits’
82
AC_ARG_ENABLE(debug,
[ --enable-debug
Turn on debugging],
[case "${enableval}" in
yes) debug=true ;;
no) debug=false ;;
*) AC_MSG_ERROR(bad value ${enableval} for --enable-debug) ;;
esac],[debug=false])
AM_CONDITIONAL(DEBUG, test x$debug = xtrue)
Here is an example of how to use that conditional in ‘Makefile.am’:
if DEBUG
DBG = debug
else
DBG =
endif
noinst_PROGRAMS = $(DBG)
This trivial example could also be handled using EXTRA_PROGRAMS (see Section 7.1.4
[Conditional Programs], page 33).
You may only test a single variable in an if statement, possibly negated using ‘!’. The
else statement may be omitted. Conditionals may be nested to any depth. You may
specify an argument to else in which case it must be the negation of the condition used
for the current if. Similarly you may specify the condition that is closed by an end:
if DEBUG
DBG = debug
else !DEBUG
DBG =
endif !DEBUG
Unbalanced conditions are errors.
Note that conditionals in Automake are not the same as conditionals in GNU Make.
Automake conditionals are checked at configure time by the ‘configure’ script, and affect
the translation from ‘Makefile.in’ to ‘Makefile’. They are based on options passed to
‘configure’ and on results that ‘configure’ has discovered about the host system. GNU
Make conditionals are checked at make time, and are based on variables passed to the make
program or defined in the ‘Makefile’.
Automake conditionals will work with any make program.
20 The effect of ‘--gnu’ and ‘--gnits’
The ‘--gnu’ option (or ‘gnu’ in the AUTOMAKE_OPTIONS variable) causes automake to check
the following:
• The files ‘INSTALL’, ‘NEWS’, ‘README’, ‘AUTHORS’, and ‘ChangeLog’, plus one of
‘COPYING.LIB’, ‘COPYING.LESSER’ or ‘COPYING’, are required at the topmost directory
of the package.
• The options ‘no-installman’ and ‘no-installinfo’ are prohibited.
Chapter 21: The effect of ‘--cygnus’
83
Note that this option will be extended in the future to do even more checking; it is
advisable to be familiar with the precise requirements of the GNU standards. Also, ‘--gnu’
can require certain non-standard GNU programs to exist for use by various maintainer-only
rules; for instance, in the future pathchk might be required for ‘make dist’.
The ‘--gnits’ option does everything that ‘--gnu’ does, and checks the following as
well:
• ‘make installcheck’ will check to make sure that the ‘--help’ and ‘--version’ really
print a usage message and a version string, respectively. This is the ‘std-options’
option (see Chapter 16 [Options], page 76).
• ‘make dist’ will check to make sure the ‘NEWS’ file has been updated to the current
version.
• VERSION is checked to make sure its format complies with Gnits standards.
• If VERSION indicates that this is an alpha release, and the file ‘README-alpha’ appears
in the topmost directory of a package, then it is included in the distribution. This
is done in ‘--gnits’ mode, and no other, because this mode is the only one where
version number formats are constrained, and hence the only mode where Automake
can automatically determine whether ‘README-alpha’ should be included.
• The file ‘THANKS’ is required.
21 The effect of ‘--cygnus’
Some packages, notably GNU GCC and GNU gdb, have a build environment originally
written at Cygnus Support (subsequently renamed Cygnus Solutions, and then later purchased by Red Hat). Packages with this ancestry are sometimes referred to as “Cygnus”
trees.
A Cygnus tree has slightly different rules for how a ‘Makefile.in’ is to be constructed.
Passing ‘--cygnus’ to automake will cause any generated ‘Makefile.in’ to comply with
Cygnus rules.
Here are the precise effects of ‘--cygnus’:
• Info files are always created in the build directory, and not in the source directory.
• ‘texinfo.tex’ is not required if a Texinfo source file is specified. The assumption is that
the file will be supplied, but in a place that Automake cannot find. This assumption
is an artifact of how Cygnus packages are typically bundled.
• ‘make dist’ is not supported, and the rules for it are not generated. Cygnus-style trees
use their own distribution mechanism.
• Certain tools will be searched for in the build tree as well as in the user’s PATH. These
tools are runtest, expect, makeinfo and texi2dvi.
• ‘--foreign’ is implied.
• The options ‘no-installinfo’ and ‘no-dependencies’ are implied.
• The macros AM_MAINTAINER_MODE and AM_CYGWIN32 are required.
• The check target doesn’t depend on all.
Chapter 22: When Automake Isn’t Enough
84
GNU maintainers are advised to use ‘gnu’ strictness in preference to the special Cygnus
mode. Some day, perhaps, the differences between Cygnus trees and GNU trees will disappear (for instance, as GCC is made more standards compliant). At that time the special
Cygnus mode will be removed.
22 When Automake Isn’t Enough
In some situations, where Automake is not up to one task, one has to resort to handwritten
rules or even handwritten ‘Makefile’s.
22.1 Extending Automake Rules
With some minor exceptions (like _PROGRAMS variables being rewritten to append
‘$(EXEEXT)’), the contents of a ‘Makefile.am’ is copied to ‘Makefile.in’ verbatim.
These copying semantics means that many problems can be worked around by simply adding some make variables and rules to ‘Makefile.am’. Automake will ignore these
additions.
Since a ‘Makefile.in’ is built from data gathered from three different places
(‘Makefile.am’, ‘configure.ac’, and automake itself), it is possible to have conflicting
definitions of rules or variables. When building ‘Makefile.in’ the following priorities
are respected by automake to ensure the user always have the last word. User defined
variables in ‘Makefile.am’ have priority over variables AC_SUBSTed from ‘configure.ac’,
and AC_SUBSTed variables have priority over automake-defined variables. As far rules are
concerned, a user-defined rule overrides any automake-defined rule for the same target.
These overriding semantics make it possible to fine tune some default settings of Automake, or replace some of its rules. Overriding Automake rules is often inadvisable, particularly in the topmost directory of a package with subdirectories. The ‘-Woverride’ option
(see Chapter 4 [Invoking Automake], page 10) comes handy to catch overridden definitions.
Note that Automake does not make any difference between rules with commands and
rules that only specify dependencies. So it is not possible to append new dependencies to
an automake-defined target without redefining the entire rule.
However, various useful targets have a ‘-local’ version you can specify in your
‘Makefile.am’. Automake will supplement the standard target with these user-supplied
targets.
The targets that support a local version are all, info, dvi, ps, pdf, html, check,
install-data, install-exec, uninstall, installdirs, installcheck and the various
clean targets (mostlyclean, clean, distclean, and maintainer-clean).
Note that there are no uninstall-exec-local or uninstall-data-local targets; just
use uninstall-local. It doesn’t make sense to uninstall just data or just executables.
For instance, here is one way to erase a subdirectory during ‘make clean’ (see Chapter 12
[Clean], page 70).
clean-local:
-rm -rf testSubDir
Chapter 22: When Automake Isn’t Enough
85
Older version of this manual used to show how to use install-data-local to install a
file to some hard-coded location, but you should avoid this. (see Section 26.9 [Hard-Coded
Install Paths], page 104)
Some rule also have a way to run another rule, called a hook, after their work is done.
The hook is named after the principal target, with ‘-hook’ appended. The targets allowing
hooks are install-data, install-exec, uninstall, dist, and distcheck.
For instance, here is how to create a hard link to an installed program:
install-exec-hook:
ln $(DESTDIR)$(bindir)/program$(EXEEXT) \
$(DESTDIR)$(bindir)/proglink$(EXEEXT)
Although cheaper and more portable than symbolic links, hard links will not work everywhere (for instance, OS/2 does not have ln). Ideally you should fall back to ‘cp -p’
when ln does not work. An easy way, if symbolic links are acceptable to you, is to add AC_
PROG_LN_S to ‘configure.ac’ (see section “Particular Program Checks” in The Autoconf
Manual) and use ‘$(LN_S)’ in ‘Makefile.am’.
For instance, here is how you could install a versioned copy of a program using ‘$(LN_S)’:
install-exec-hook:
cd $(DESTDIR)$(bindir) && \
mv -f prog$(EXEEXT) prog-$(VERSION)$(EXEEXT) && \
$(LN_S) prog-$(VERSION)$(EXEEXT) prog$(EXEEXT)
Note that we rename the program so that a new version will erase the symbolic link, not
the real binary. Also we cd into the destination directory in order to create relative links.
When writing install-exec-hook or install-data-hook, please bear in mind that
the exec/data distinction is based on the installation directory, not on the primary used
(see Chapter 11 [Install], page 68). So a foo_SCRIPTS will be installed by install-data,
and a barexec_SCRIPTS will be installed by install-exec. You should define your hooks
consequently.
22.2 Third-Party ‘Makefile’s
In most projects all ‘Makefile’s are generated by Automake. In some cases, however,
projects need to embed subdirectories with handwritten ‘Makefile’s. For instance, one
subdirectory could be a third-party project with its own build system, not using Automake.
It is possible to list arbitrary directories in SUBDIRS or DIST_SUBDIRS provided each of
these directories has a ‘Makefile’ that recognizes all the following recursive targets.
When a user runs one of these targets, that target is run recursively in all subdirectories.
This is why it is important that even third-party ‘Makefile’s support them.
all
Compile the entire package. This is the default target in Automake-generated
‘Makefile’s, but it does not need to be the default in third-party ‘Makefile’s.
distdir
Copy files to distribute into ‘$(distdir)’, before a tarball is constructed. Of
course this target is not required if the ‘no-dist’ option (see Chapter 16 [Options], page 76) is used.
The variables ‘$(top_distdir)’ and ‘$(distdir)’ (see Chapter 13 [Dist],
page 70) will be passed from the outer package to the subpackage when the
Chapter 22: When Automake Isn’t Enough
86
distdir target is invoked. These two variables have been adjusted for the
directory that is being recursed into, so they are ready to use.
install
install-data
install-exec
uninstall
Install or uninstall files (see Chapter 11 [Install], page 68).
install-info
Install only the Texinfo documentation (see Section 10.1 [Texinfo], page 65).
installdirs
Create install directories, but do not install any files.
check
installcheck
Check the package (see Chapter 14 [Tests], page 73).
mostlyclean
clean
distclean
maintainer-clean
Cleaning rules (see Chapter 12 [Clean], page 70).
dvi
pdf
ps
info
html
tags
ctags
Build the documentation in various formats (see Section 10.1 [Texinfo],
page 65).
Build ‘TAGS’ and ‘CTAGS’ (see Section 17.1 [Tags], page 79).
If you have ever used Gettext in a project, this is a good example of how third-party
‘Makefile’s can be used with Automake. The ‘Makefile’s gettextize puts in the ‘po/’
and ‘intl/’ directories are handwritten ‘Makefile’s that implement all these targets. That
way they can be added to SUBDIRS in Automake packages.
Directories that are only listed in DIST_SUBDIRS but not in SUBDIRS need only the
distclean, maintainer-clean, and distdir rules (see Section 6.2 [Conditional Subdirectories], page 25).
Usually, many of these rules are irrelevant to the third-party subproject, but they are
required for the whole package to work. It’s OK to have a rule that does nothing, so if
you are integrating a third-party project with no documentation or tag support, you could
simply augment its ‘Makefile’ as follows:
EMPTY_AUTOMAKE_TARGETS = dvi pdf ps info html tags ctags
.PHONY: $(EMPTY_AUTOMAKE_TARGETS)
$(EMPTY_AUTOMAKE_TARGETS):
Another aspect of integrating third-party build systems is whether they support VPATH
builds. Obviously if the subpackage does not support VPATH builds the whole package will
Chapter 22: When Automake Isn’t Enough
87
not support VPATH builds. This in turns means that ‘make distcheck’ will not work,
because it relies on VPATH builds. Some people can live without this (actually, many Automake users have never heard of ‘make distcheck’). Other people may prefer to revamp the
existing ‘Makefile’s to support VPATH. Doing so does not necessarily require Automake,
only Autoconf is needed (see section “Build Directories” in The Autoconf Manual). The
necessary substitutions: ‘@scrdir@’, ‘@top_srcdir@’, and ‘@top_builddir@’ are defined
by ‘configure’ when it processes a ‘Makefile’ (see section “Preset Output Variables” in
The Autoconf Manual), they are not computed by the Makefile like the aforementioned
‘$(distdir)’ and ‘$(top_distdir)’ variables..
It is sometimes inconvenient to modify a third-party ‘Makefile’ to introduce the above
required targets. For instance, one may want to keep the third-party sources untouched to
ease upgrades to new versions.
Here are two other ideas. If GNU make is assumed, one possibility is to add to that
subdirectory a ‘GNUmakefile’ that defines the required targets and include the third-party
‘Makefile’. For this to work in VPATH builds, ‘GNUmakefile’ must lie in the build directory; the easiest way to do this is to write a ‘GNUmakefile.in’ instead, and have it processed
with AC_CONFIG_FILES from the outer package. For example if we assume ‘Makefile’ defines all targets except the documentation targets, and that the check target is actually
called test, we could write ‘GNUmakefile’ (or ‘GNUmakefile.in’) like this:
# First, include the real Makefile
include Makefile
# Then, define the other targets needed by Automake Makefiles.
.PHONY: dvi pdf ps info html check
dvi pdf ps info html:
check: test
A similar idea that does not use include is to write a proxy ‘Makefile’ that dispatches
rules to the real ‘Makefile’, either with ‘$(MAKE) -f Makefile.real $(AM_MAKEFLAGS)
target’ (if it’s OK to rename the original ‘Makefile’) or with ‘cd subdir && $(MAKE)
$(AM_MAKEFLAGS) target’ (if it’s OK to store the subdirectory project one directory
deeper). The good news is that this proxy ‘Makefile’ can be generated with Automake.
All we need are ‘-local’ targets (see Section 22.1 [Extending], page 84) that perform the
dispatch. Of course the other Automake features are available, so you could decide to let
Automake perform distribution or installation. Here is a possible ‘Makefile.am’:
all-local:
cd subdir && $(MAKE) $(AM_MAKEFLAGS) all
check-local:
cd subdir && $(MAKE) $(AM_MAKEFLAGS) test
clean-local:
cd subdir && $(MAKE) $(AM_MAKEFLAGS) clean
# Assuming the package knows how to install itself
install-data-local:
cd subdir && $(MAKE) $(AM_MAKEFLAGS) install-data
install-exec-local:
cd subdir && $(MAKE) $(AM_MAKEFLAGS) install-exec
uninstall-local:
Chapter 24: Automake API versioning
88
cd subdir && $(MAKE) $(AM_MAKEFLAGS) uninstall
# Distribute files from here.
EXTRA_DIST = subdir/Makefile subdir/program.c ...
Pushing this idea to the extreme, it is also possible to ignore the subproject build system
and build everything from this proxy ‘Makefile.am’. This might sounds very sensible if
you need VPATH builds but the subproject does not support them.
23 Distributing ‘Makefile.in’s
Automake places no restrictions on the distribution of the resulting ‘Makefile.in’s. We
still encourage software authors to distribute their work under terms like those of the GPL,
but doing so is not required to use Automake.
Some of the files that can be automatically installed via the ‘--add-missing’ switch do
fall under the GPL. However, these also have a special exception allowing you to distribute
them with your package, regardless of the licensing you choose.
24 Automake API versioning
New Automake releases usually include bug fixes and new features. Unfortunately they
may also introduce new bugs and incompatibilities. This makes four reasons why a package
may require a particular Automake version.
Things get worse when maintaining a large tree of packages, each one requiring a different
version of Automake. In the past, this meant that any developer (and sometime users) had
to install several versions of Automake in different places, and switch ‘$PATH’ appropriately
for each package.
Starting with version 1.6, Automake installs versioned binaries. This means you can
install several versions of Automake in the same ‘$prefix’, and can select an arbitrary Automake version by running automake-1.6 or automake-1.7 without juggling with ‘$PATH’.
Furthermore, ‘Makefile’’s generated by Automake 1.6 will use automake-1.6 explicitly in
their rebuild rules.
The number ‘1.6’ in automake-1.6 is Automake’s API version, not Automake’s version.
If a bug fix release is made, for instance Automake 1.6.1, the API version will remain 1.6.
This means that a package that works with Automake 1.6 should also work with 1.6.1; after
all, this is what people expect from bug fix releases.
If your package relies on a feature or a bug fix introduced in a release, you can pass this
version as an option to Automake to ensure older releases will not be used. For instance,
use this in your ‘configure.ac’:
AM_INIT_AUTOMAKE(1.6.1)
dnl Require Automake 1.6.1 or better.
or, in a particular ‘Makefile.am’:
AUTOMAKE_OPTIONS = 1.6.1
# Require Automake 1.6.1 or better.
Automake will print an error message if its version is older than the requested version.
Chapter 26: Frequently Asked Questions about Automake
89
What is in the API
Automake’s programming interface is not easy to define. Basically it should include at least
all documented variables and targets that a ‘Makefile.am’ author can use, any behavior
associated with them (e.g., the places where ‘-hook’’s are run), the command line interface
of automake and aclocal, . . .
What is not in the API
Every undocumented variable, target, or command line option, is not part of the API. You
should avoid using them, as they could change from one version to the other (even in bug
fix releases, if this helps to fix a bug).
If it turns out you need to use such a undocumented feature, contact automake@gnu.org
and try to get it documented and exercised by the test-suite.
25 Upgrading a Package to a Newer Automake
Version
Automake maintains three kind of files in a package.
• ‘aclocal.m4’
• ‘Makefile.in’s
• auxiliary tools like ‘install-sh’ or ‘py-compile’
‘aclocal.m4’ is generated by aclocal and contains some Automake-supplied M4 macros.
Auxiliary tools are installed by ‘automake --add-missing’ when needed. ‘Makefile.in’s
are built from ‘Makefile.am’ by automake, and rely on the definitions of the M4 macros
put in ‘aclocal.m4’ as well as the behavior of the auxiliary tools installed.
Because all these files are closely related, it is important to regenerate all of them when
upgrading to a newer Automake release. The usual way to do that is
aclocal # with any option needed (such a -I m4)
autoconf
automake --add-missing --force-missing
or more conveniently:
autoreconf -vfi
The use of ‘--force-missing’ ensures that auxiliary tools will be overridden by new
versions (see Chapter 4 [Invoking Automake], page 10).
It is important to regenerate all these files each time Automake is upgraded, even between
bug fixes releases. For instance, it is not unusual for a bug fix to involve changes to both the
rules generated in ‘Makefile.in’ and the supporting M4 macros copied to ‘aclocal.m4’.
Presently automake is able to diagnose situations where ‘aclocal.m4’ has been generated
with another version of aclocal. However it never checks whether auxiliary scripts are upto-date. In other words, automake will tell you when aclocal needs to be rerun, but it will
never diagnose a missing ‘--force-missing’.
Before upgrading to a new major release, it is a good idea to read the file ‘NEWS’. This
file lists all changes between releases: new features, obsolete constructs, known incompatibilities, and workarounds.
Chapter 26: Frequently Asked Questions about Automake
90
26 Frequently Asked Questions about Automake
This chapter covers some questions that often come up on the mailing lists.
26.1 CVS and generated files
26.1.1 Background: distributed generated files
Packages made with Autoconf and Automake ship with some generated files like ‘configure’
or ‘Makefile.in’. These files were generated on the developer’s host and are distributed
so that end-users do not have to install the maintainer tools required to rebuild them.
Other generated files like Lex scanners, Yacc parsers, or Info documentation, are usually
distributed on similar grounds.
Automake outputs rules in ‘Makefile’s to rebuild these files. For instance, make will run
autoconf to rebuild ‘configure’ whenever ‘configure.ac’ is changed. This makes development safer by ensuring a ‘configure’ is never out-of-date with respect to ‘configure.ac’.
As generated files shipped in packages are up-to-date, and because tar preserves timestamps, these rebuild rules are not triggered when a user unpacks and builds a package.
26.1.2 Background: CVS and timestamps
Unless you use CVS keywords (in which case files must be updated at commit time), CVS
preserves timestamp during ‘cvs commit’ and ‘cvs import -d’ operations.
When you check out a file using ‘cvs checkout’ its timestamp is set to that of the
revision that is being checked out.
However, during cvs update, files will have the date of the update, not the original
timestamp of this revision. This is meant to make sure that make notices sources files have
been updated.
This timestamp shift is troublesome when both sources and generated files are kept
under CVS. Because CVS processes files in alphabetical order, ‘configure.ac’ will appear
older than ‘configure’ after a cvs update that updates both files, even if ‘configure’
was newer than ‘configure.ac’ when it was checked in. Calling make will then trigger a
spurious rebuild of ‘configure’.
26.1.3 Living with CVS in Autoconfiscated projects
There are basically two clans amongst maintainers: those who keep all distributed files
under CVS, including generated files, and those who keep generated files out of CVS.
All files in CVS
• The CVS repository contains all distributed files so you know exactly what is distributed, and you can checkout any prior version entirely.
• Maintainers can see how generated files evolve (for instance, you can see what happens
to your ‘Makefile.in’s when you upgrade Automake and make sure they look OK).
• Users do not need the autotools to build a checkout of the project, it works just like a
released tarball.
Chapter 26: Frequently Asked Questions about Automake
91
• If users use cvs update to update their copy, instead of cvs checkout to fetch a fresh
one, timestamps will be inaccurate. Some rebuild rules will be triggered and attempt
to run developer tools such as autoconf or automake.
Actually, calls to such tools are all wrapped into a call to the missing script discussed
later (see Section 26.2 [maintainer-mode], page 92). missing will take care of fixing
the timestamps when these tools are not installed, so that the build can continue.
• In distributed development, developers are likely to have different version of the maintainer tools installed. In this case rebuilds triggered by timestamp lossage will lead to
spurious changes to generated files. There are several solutions to this:
• All developers should use the same versions, so that the rebuilt files are identical
to files in CVS. (This starts to be difficult when each project you work on uses
different versions.)
• Or people use a script to fix the timestamp after a checkout (the GCC folks have
such a script).
• Or ‘configure.ac’ uses AM_MAINTAINER_MODE, which will disable all these rebuild rules by default. This is further discussed in Section 26.2 [maintainer-mode],
page 92.
• Although we focused on spurious rebuilds, the converse can also happen. CVS’s timestamp handling can also let you think an out-of-date file is up-to-date.
For instance, suppose a developer has modified ‘Makefile.am’ and has rebuilt
‘Makefile.in’. He then decide to do a last-minute change to ‘Makefile.am’ right
before checking in both files (without rebuilding ‘Makefile.in’ to account for the
change).
This last change to ‘Makefile.am’ make the copy of ‘Makefile.in’ out-of-date. Since
CVS processes files alphabetically, when another developer ‘cvs update’ his or her tree,
‘Makefile.in’ will happen to be newer than ‘Makefile.am’. This other developer will
not see ‘Makefile.in’ is out-of-date.
Generated files out of CVS
One way to get CVS and make working peacefully is to never store generated files in CVS,
i.e., do not CVS-control files that are ‘Makefile’ targets (also called derived files).
This way developers are not annoyed by changes to generated files. It does not
matter if they all have different versions (assuming they are compatible, of course).
And finally, timestamps are not lost, changes to sources files can’t be missed as in the
‘Makefile.am’/‘Makefile.in’ example discussed earlier.
The drawback is that the CVS repository is not an exact copy of what is distributed
and that users now need to install various development tools (maybe even specific versions)
before they can build a checkout. But, after all, CVS’s job is versioning, not distribution.
Allowing developers to use different versions of their tools can also hide bugs during
distributed development. Indeed, developers will be using (hence testing) their own generated files, instead of the generated files that will be released actually. The developer
who prepares the tarball might be using a version of the tool that produces bogus output
(for instance a non-portable C file), something other developers could have noticed if they
weren’t using their own versions of this tool.
Chapter 26: Frequently Asked Questions about Automake
92
26.1.4 Third-party files
Another class of files not discussed here (because they do not cause timestamp issues) are
files that are shipped with a package, but maintained elsewhere. For instance, tools like
gettextize and autopoint (from Gettext) or libtoolize (from Libtool), will install or
update files in your package.
These files, whether they are kept under CVS or not, raise similar concerns about version
mismatch between developers’ tools. The Gettext manual has a section about this, see
section “Integrating with CVS” in GNU gettext tools.
26.2 missing and AM_MAINTAINER_MODE
26.2.1 missing
The missing script is a wrapper around several maintainer tools, designed to warn users if a
maintainer tool is required but missing. Typical maintainer tools are autoconf, automake,
bison, etc. Because file generated by these tools are shipped with the other sources of a
package, these tools shouldn’t be required during a user build and they are not checked for
in ‘configure’.
However, if for some reason a rebuild rule is triggered and involves a missing tool,
missing will notice it and warn the user. Besides the warning, when a tool is missing,
missing will attempt to fix timestamps in a way that allows the build to continue. For
instance, missing will touch ‘configure’ if autoconf is not installed. When all distributed
files are kept under CVS, this feature of missing allows user with no maintainer tools to
build a package off CVS, bypassing any timestamp inconsistency implied by ‘cvs update’.
If the required tool is installed, missing will run it and won’t attempt to continue after
failures. This is correct during development: developers love fixing failures. However, users
with wrong versions of maintainer tools may get an error when the rebuild rule is spuriously
triggered, halting the build. This failure to let the build continue is one of the arguments
of the AM_MAINTAINER_MODE advocates.
26.2.2 AM_MAINTAINER_MODE
AM_MAINTAINER_MODE disables the so called "rebuild rules" by default. If you have
AM_MAINTAINER_MODE in ‘configure.ac’, and run ‘./configure && make’, then make
will *never* attempt to rebuilt ‘configure’, ‘Makefile.in’s, Lex or Yacc outputs, etc.
I.e., this disables build rules for files that are usually distributed and that users should
normally not have to update.
If you run ‘./configure --enable-maintainer-mode’, then these rebuild rules will be
active.
People use AM_MAINTAINER_MODE either because they do want their users (or themselves)
annoyed by timestamps lossage (see Section 26.1 [CVS], page 90), or because they simply
can’t stand the rebuild rules and prefer running maintainer tools explicitly.
AM_MAINTAINER_MODE also allows you to disable some custom build rules conditionally.
Some developers use this feature to disable rules that need exotic tools that users may not
have available.
Several years ago François Pinard pointed out several arguments against this
AM_MAINTAINER_MODE macro. Most of them relate to insecurity. By removing dependencies
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you get non-dependable builds: change to sources files can have no effect on generated
files and this can be very confusing when unnoticed. He adds that security shouldn’t be
reserved to maintainers (what ‘--enable-maintainer-mode’ suggests), on the contrary. If
one user has to modify a ‘Makefile.am’, then either ‘Makefile.in’ should be updated or
a warning should be output (this is what Automake uses missing for) but the last thing
you want is that nothing happens and the user doesn’t notice it (this is what happens
when rebuild rules are disabled by AM_MAINTAINER_MODE).
Jim Meyering, the inventor of the AM_MAINTAINER_MODE macro was swayed by François’s
arguments, and got rid of AM_MAINTAINER_MODE in all of his packages.
Still many people continue to use AM_MAINTAINER_MODE, because it helps them working
on projects where all files are kept under CVS, and because missing isn’t enough if you
have the wrong version of the tools.
26.3 Why doesn’t Automake support wildcards?
Developers are lazy. They often would like to use wildcards in ‘Makefile.am’s, so they
don’t need to remember they have to update ‘Makefile.am’s every time they add, delete,
or rename a file.
There are several objections to this:
• When using CVS (or similar) developers need to remember they have to run ‘cvs add’
or ‘cvs rm’ anyway. Updating ‘Makefile.am’ accordingly quickly becomes a reflex.
Conversely, if your application doesn’t compile because you forgot to add a file in
‘Makefile.am’, it will help you remember to ‘cvs add’ it.
• Using wildcards makes easy to distribute files by mistake. For instance, some code a
developer is experimenting with (a test case, say) but that should not be part of the
distribution.
• Using wildcards it’s easy to omit some files by mistake. For instance, one developer
creates a new file, uses it at many places, but forget to commit it. Another developer
then checkout the incomplete project and is able to run ‘make dist’ successfully, even
though a file is missing.
• Listing files, you control *exactly* what you distribute. If some file that should be
distributed is missing from your tree, ‘make dist’ will complain. Besides, you don’t
distribute more than what you listed.
• Finally it’s really hard to ‘forget’ adding a file to ‘Makefile.am’, because if you don’t
add it, it doesn’t get compiled nor installed, so you can’t even test it.
Still, these are philosophical objections, and as such you may disagree, or find enough
value in wildcards to dismiss all of them. Before you start writing a patch against Automake
to teach it about wildcards, let’s see the main technical issue: portability.
Although ‘$(wildcard ...)’ works with GNU make, it is not portable to other make
implementations.
The only way Automake could support $(wildcard ...) is by expending $(wildcard
...) when automake is run. Resulting ‘Makefile.in’s would be portable since they would
list all files and not use ‘$(wildcard ...)’. However that means developers need to remember they must run automake each time they add, delete, or rename files.
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Compared to editing ‘Makefile.am’, this is really little win. Sure, it’s easier and faster
to type ‘automake; make’ than to type ‘emacs Makefile.am; make’. But nobody bothered
enough to write a patch add support for this syntax. Some people use scripts to generated
file lists in ‘Makefile.am’ or in separate ‘Makefile’ fragments.
Even if you don’t care about portability, and are tempted to use ‘$(wildcard ...)’
anyway because you target only GNU Make, you should know there are many places where
Automake need to know exactly which files should be processed. As Automake doesn’t
know how to expand ‘$(wildcard ...)’, you cannot use it in these places. ‘$(wildcard
...)’ is a black box comparable to AC_SUBSTed variables as far Automake is concerned.
You can get warnings about ‘$(wildcard ...’) constructs using the ‘-Wportability’
flag.
26.4 Files left in build directory after distclean
This is a diagnostic you might encounter while running ‘make distcheck’.
As explained in Chapter 13 [Dist], page 70, ‘make distcheck’ attempts to build and
check your package for errors like this one.
‘make distcheck’ will perform a VPATH build of your package, and then call ‘make
distclean’. Files left in the build directory after ‘make distclean’ has run are listed
after this error.
This diagnostic really covers two kinds of errors:
• files that are forgotten by distclean;
• distributed files that are erroneously rebuilt.
The former left-over files are not distributed, so the fix is to mark them for cleaning (see
Chapter 12 [Clean], page 70), this is obvious and doesn’t deserve more explanations.
The latter bug is not always easy to understand and fix, so let’s proceed with an example. Suppose our package contains a program for which we want to build a man page
using help2man. GNU help2man produces simple manual pages from the ‘--help’ and
‘--version’ output of other commands (see section “Overview” in The Help2man Manual). Because we don’t to force want our users to install help2man, we decide to distribute
the generated man page using the following setup.
# This Makefile.am is bogus.
bin_PROGRAMS = foo
foo_SOURCES = foo.c
dist_man_MANS = foo.1
foo.1: foo$(EXEEXT)
help2man --output=foo.1 ./foo$(EXEEXT)
This will effectively distribute the man page. However, ‘make distcheck’ will fail with:
ERROR: files left in build directory after distclean:
./foo.1
Why was ‘foo.1’ rebuilt? Because although distributed, ‘foo.1’ depends on a nondistributed built file: ‘foo$(EXEEXT)’. ‘foo$(EXEEXT)’ is built by the user, so it will always
appear to be newer than the distributed ‘foo.1’.
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‘make distcheck’ caught an inconsistency in our package. Our intent was to distribute
‘foo.1’ so users do not need installing help2man, however since this our rule causes this file
to be always rebuilt, users do need help2man. Either we should ensure that ‘foo.1’ is not
rebuilt by users, or there is no point in distributing ‘foo.1’.
More generally, the rule is that distributed files should never depend on non-distributed
built files. If you distribute something generated, distribute its sources.
One way to fix the above example, while still distributing ‘foo.1’ is to not depend on
‘foo$(EXEEXT)’. For instance, assuming foo --version and foo --help do not change
unless ‘foo.c’ or ‘configure.ac’ change, we could write the following ‘Makefile.am’:
bin_PROGRAMS = foo
foo_SOURCES = foo.c
dist_man_MANS = foo.1
foo.1: foo.c $(top_srcdir)/configure.ac
$(MAKE) $(AM_MAKEFLAGS) foo$(EXEEXT)
help2man --output=foo.1 ./foo$(EXEEXT)
This way, ‘foo.1’ will not get rebuilt every time ‘foo$(EXEEXT)’ changes. The make
call makes sure ‘foo$(EXEEXT)’ is up-to-date before help2man. Another way to ensure this
would be to use separate directories for binaries and man pages, and set SUBDIRS so that
binaries are built before man pages.
We could also decide not to distribute ‘foo.1’. In this case it’s fine to have ‘foo.1’
dependent upon ‘foo$(EXEEXT)’, since both will have to be rebuilt. However it would be
impossible to build the package in a cross-compilation, because building ‘foo.1’ involves
an execution of ‘foo$(EXEEXT)’.
Another context where such errors are common is when distributed files are built by
tools that are built by the package. The pattern is similar:
distributed-file: built-tools distributed-sources
build-command
should be changed to
distributed-file: distributed-sources
$(MAKE) $(AM_MAKEFLAGS) built-tools
build-command
or you could choose not to distribute ‘distributed-file’, if cross-compilation does not
matter.
The points made through these examples are worth a summary:
• Distributed files should never depend upon non-distributed built files.
• Distributed files should be distributed will all their dependencies.
• If a file is intended be rebuilt by users, there is no point in distributing it.
For desperate cases, it’s always possible to disable this check by setting distcleancheck_
listfiles as documented in Chapter 13 [Dist], page 70. Make sure you do understand the
reason why ‘make distcheck’ complains before you do this. distcleancheck_listfiles
is a way to hide errors, not to fix them. You can always do better.
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96
26.5 Flag Variables Ordering
What is the difference between AM_CFLAGS, CFLAGS, and
mumble_CFLAGS?
Why does automake output CPPFLAGS after
AM_CPPFLAGS on compile lines? Shouldn’t it be the converse?
My ‘configure’ adds some warning flags into CXXFLAGS. In
one ‘Makefile.am’ I would like to append a new flag, however if I
put the flag into AM_CXXFLAGS it is prepended to the other
flags, not appended.
26.5.1 Compile Flag Variables
This section attempts to answer all the above questions. We will mostly discuss CPPFLAGS
in our examples, but actually the answer holds for all the compile flags used in Automake:
CCASFLAGS, CFLAGS, CPPFLAGS, CXXFLAGS, FCFLAGS, FFLAGS, GCJFLAGS, LDFLAGS, LFLAGS,
OBJCFLAGS, RFLAGS, and YFLAGS.
CPPFLAGS, AM_CPPFLAGS, and mumble_CPPFLAGS are three variables that can be used to
pass flags to the C preprocessor (actually these variables are also used for other languages
like C++ or preprocessed Fortran). CPPFLAGS is the user variable (see Section 2.5 [User
Variables], page 4), AM_CPPFLAGS is the Automake variable, and mumble_CPPFLAGS is the
variable specific to the mumble target (we call this a per-target variable, see Section 7.4
[Program and Library Variables], page 40).
Automake always uses two of these variables when compiling C sources files. When
compiling an object file for the mumble target, the first variable will be mumble_CPPFLAGS
if it is defined, or AM_CPPFLAGS otherwise. The second variable is always CPPFLAGS.
In the following example,
bin_PROGRAMS = foo bar
foo_SOURCES = xyz.c
bar_SOURCES = main.c
foo_CPPFLAGS = -DFOO
AM_CPPFLAGS = -DBAZ
‘xyz.o’ will be compiled with ‘$(foo_CPPFLAGS) $(CPPFLAGS)’, (because ‘xyz.o’ is part
of the foo target), while ‘main.o’ will be compiled with ‘$(AM_CPPFLAGS) $(CPPFLAGS)’
(because there is no per-target variable for target bar).
The difference between mumble_CPPFLAGS and AM_CPPFLAGS being clear enough, let’s
focus on CPPFLAGS. CPPFLAGS is a user variable, i.e., a variable that users are entitled to
modify in order to compile the package. This variable, like many others, is documented at
the end of the output of ‘configure --help’.
For instance, someone who needs to add ‘/home/my/usr/include’ to the C compiler’s
search path would configure a package with
./configure CPPFLAGS=’-I /home/my/usr/include’
and this flag would be propagated to the compile rules of all ‘Makefile’s.
It is also not uncommon to override a user variable at make-time. Many installers do
this with prefix, but this can be useful with compiler flags too. For instance, if, while
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debugging a C++ project, you need to disable optimization in one specific object file, you
can run something like
rm file.o
make CXXFLAGS=-O0 file.o
make
The reason ‘$(CPPFLAGS)’ appears after ‘$(AM_CPPFLAGS)’ or ‘$(mumble_CPPFLAGS)’ in
the compile command is that users should always have the last say. It probably makes
more sense if you think about it while looking at the ‘CXXFLAGS=-O0’ above, which should
supersede any other switch from AM_CXXFLAGS or mumble_CXXFLAGS (and this of course
replaces the previous value of CXXFLAGS).
You should never redefine a user variable such as CPPFLAGS in ‘Makefile.am’. Use
‘automake -Woverride’ to diagnose such mistakes. Even something like
CPPFLAGS = -DDATADIR=\"$(datadir)\" @CPPFLAGS@
is erroneous. Although this preserves ‘configure’’s value of CPPFLAGS, the definition of
DATADIR will disappear if a user attempts to override CPPFLAGS from the make command
line.
AM_CPPFLAGS = -DDATADIR=\"$(datadir)\"
is all what is needed here if no per-target flags are used.
You should not add options to these user variables within ‘configure’ either, for the
same reason. Occasionally you need to modify these variables to perform a test, but you
should reset their values afterwards. In contrast, it is OK to modify the ‘AM_’ variables
within ‘configure’ if you AC_SUBST them, but it is rather rare that you need to do this, unless you really want to change the default definitions of the ‘AM_’ variables in all ‘Makefile’s.
What we recommend is that you define extra flags in separate variables. For instance, you
may write an Autoconf macro that computes a set of warning options for the C compiler, and
AC_SUBST them in WARNINGCFLAGS; you may also have an Autoconf macro that determines
which compiler and which linker flags should be used to link with library ‘libfoo’, and
AC_SUBST these in LIBFOOCFLAGS and LIBFOOLDFLAGS. Then, a ‘Makefile.am’ could use
these variables as follows:
AM_CFLAGS = $(WARNINGCFLAGS)
bin_PROGRAMS = prog1 prog2
prog1_SOURCES = ...
prog2_SOURCES = ...
prog2_CFLAGS = $(LIBFOOCFLAGS) $(AM_CFLAGS)
prog2_LDFLAGS = $(LIBFOOLDFLAGS)
In this example both programs will be compiled with the flags substituted into
‘$(WARNINGCFLAGS)’, and prog2 will additionally be compiled with the flags required to
link with ‘libfoo’.
Note that listing AM_CFLAGS in a per-target CFLAGS variable is a common idiom to ensure
that AM_CFLAGS applies to every target in a ‘Makefile.in’.
Using variables like this gives you full control over the ordering of the flags. For instance,
if there is a flag in $(WARNINGCFLAGS) that you want to negate for a particular target,
you can use something like ‘prog1_CFLAGS = $(AM_CFLAGS) -no-flag’. If all these flags
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had been forcefully appended to CFLAGS, there would be no way to disable one flag. Yet
another reason to leave user variables to users.
Finally, we have avoided naming the variable of the example LIBFOO_LDFLAGS (with an
underscore) because that would cause Automake to think that this is actually a per-target
variable (like mumble_LDFLAGS) for some non-declared LIBFOO target.
26.5.2 Other Variables
There are other variables in Automake that follow similar principles to allow user options.
For instance, Texinfo rules (see Section 10.1 [Texinfo], page 65) use MAKEINFOFLAGS
and AM_MAKEINFOFLAGS. Similarly, DejaGnu tests (see Chapter 14 [Tests], page 73)
use RUNTESTDEFAULTFLAGS and AM_RUNTESTDEFAULTFLAGS. The tags and ctags rules
(see Section 17.1 [Tags], page 79) use ETAGSFLAGS, AM_ETAGSFLAGS, CTAGSFLAGS, and
AM_CTAGSFLAGS. Java rules (see Section 9.4 [Java], page 63) use JAVACFLAGS and
AM_JAVACFLAGS. None of these rules do support per-target flags (yet).
To some extent, even AM_MAKEFLAGS (see Section 6.1 [Subdirectories], page 25) obeys this
naming scheme. The slight difference is that MAKEFLAGS is passed to sub-makes implicitly
by make itself.
However you should not think that all variables ending with FLAGS follow this convention.
For instance, DISTCHECK_CONFIGURE_FLAGS (see Chapter 13 [Dist], page 70), ACLOCAL_
AMFLAGS (see Chapter 15 [Rebuilding], page 75 and Section 5.8 [Local Macros], page 23),
are two variables that are only useful to the maintainer and have no user counterpart.
ARFLAGS (see Section 7.2 [A Library], page 34) is usually defined by Automake and has
neither AM_ nor per-target cousin.
Finally you should not think either that the existence of a per-target variable implies that
of an AM_ variable or that of a user variable. For instance, the mumble_LDADD per-target
variable overrides the global LDADD variable (which is not a user variable), and mumble_
LIBADD exists only as a per-target variable. See Section 7.4 [Program and Library Variables],
page 40.
26.6 Why are object files sometimes renamed?
This happens when per-target compilation flags are used. Object files need to be renamed
just in case they would clash with object files compiled from the same sources, but with
different flags. Consider the following example.
bin_PROGRAMS = true false
true_SOURCES = generic.c
true_CPPFLAGS = -DEXIT_CODE=0
false_SOURCES = generic.c
false_CPPFLAGS = -DEXIT_CODE=1
Obviously the two programs are built from the same source, but it would be bad if they
shared the same object, because ‘generic.o’ cannot be built with both ‘-DEXIT_CODE=0’
and ‘-DEXIT_CODE=1’. Therefore automake outputs rules to build two different objects:
‘true-generic.o’ and ‘false-generic.o’.
automake doesn’t actually look whether source files are shared to decide if it must rename
objects. It will just rename all objects of a target as soon as it sees per-target compilation
flags are used.
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It’s OK to share object files when per-target compilation flags are not used. For instance,
‘true’ and ‘false’ will both use ‘version.o’ in the following example.
AM_CPPFLAGS = -DVERSION=1.0
bin_PROGRAMS = true false
true_SOURCES = true.c version.c
false_SOURCES = false.c version.c
Note that the renaming of objects is also affected by the _SHORTNAME variable (see
Section 7.4 [Program and Library Variables], page 40).
26.7 Per-Object Flags Emulation
One of my source files needs to be compiled with different flags. How
do I do?
Automake supports per-program and per-library compilation flags (see Section 7.4 [Program and Library Variables], page 40 and Section 26.5 [Flag Variables Ordering], page 96).
With this you can define compilation flags that apply to all files compiled for a target. For
instance, in
bin_PROGRAMS = foo
foo_SOURCES = foo.c foo.h bar.c bar.h main.c
foo_CFLAGS = -some -flags
‘foo-foo.o’, ‘foo-bar.o’, and ‘foo-main.o’ will all be compiled with ‘-some -flags’.
(If you wonder about the names of these object files, see Section 26.6 [renamed objects],
page 98.) Note that foo_CFLAGS gives the flags to use when compiling all the C sources of
the program foo, it has nothing to do with ‘foo.c’ or ‘foo-foo.o’ specifically.
What if ‘foo.c’ needs to be compiled into ‘foo.o’ using some specific flags, that none of
the other files require? Obviously per-program flags are not directly applicable here. Something like per-object flags are expected, i.e., flags that would be used only when creating
‘foo-foo.o’. Automake does not support that, however this is easy to simulate using a
library that contains only that object, and compiling this library with per-library flags.
bin_PROGRAMS = foo
foo_SOURCES = bar.c bar.h main.c
foo_CFLAGS = -some -flags
foo_LDADD = libfoo.a
noinst_LIBRARIES = libfoo.a
libfoo_a_SOURCES = foo.c foo.h
libfoo_a_CFLAGS = -some -other -flags
Here ‘foo-bar.o’ and ‘foo-main.o’ will all be compiled with ‘-some -flags’, while
‘libfoo_a-foo.o’ will be compiled using ‘-some -other -flags’. Eventually, all three
objects will be linked to form ‘foo’.
This trick can also be achieved using Libtool convenience libraries, for instance
‘noinst_LTLIBRARIES = libfoo.la’ (see Section 7.3.5 [Libtool Convenience Libraries],
page 37).
Another tempting idea to implement per-object flags is to override the compile rules
automake would output for these files. Automake will not define a rule for a target you
have defined, so you could think about defining the ‘foo-foo.o: foo.c’ rule yourself. We
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recommend against this, because this is error prone. For instance, if you add such a rule to
the first example, it will break the day you decide to remove foo_CFLAGS (because ‘foo.c’
will then be compiled as ‘foo.o’ instead of ‘foo-foo.o’, see Section 26.6 [renamed objects],
page 98). Also in order to support dependency tracking, the two ‘.o’/‘.obj’ extensions,
and all the other flags variables involved in a compilation, you will end up modifying a
copy of the rule previously output by automake for this file. If a new release of Automake
generates a different rule, your copy will need to be updated by hand.
26.8 Handling Tools that Produce Many Outputs
This section describes a make idiom that can be used when a tool produces multiple output
files. It is not specific to Automake and can be used in ordinary ‘Makefile’s.
Suppose we have a program called foo that will read one file called ‘data.foo’ and
produce two files named ‘data.c’ and ‘data.h’. We want to write a ‘Makefile’ rule that
captures this one-to-two dependency.
The naive rule is incorrect:
# This is incorrect.
data.c data.h: data.foo
foo data.foo
What the above rule really says is that ‘data.c’ and ‘data.h’ each depend on ‘data.foo’,
and can each be built by running ‘foo data.foo’. In other words it is equivalent to:
# We do not want this.
data.c: data.foo
foo data.foo
data.h: data.foo
foo data.foo
which means that foo can be run twice. Usually it will not be run twice, because make
implementations are smart enough to check for the existence of the second file after the
first one has been built; they will therefore detect that it already exists. However there are
a few situations where it can run twice anyway:
• The most worrying case is when running a parallel make. If ‘data.c’ and ‘data.h’ are
built in parallel, two ‘foo data.foo’ commands will run concurrently. This is harmful.
• Another case is when the dependency (here ‘data.foo’) is (or depends upon) a phony
target.
A solution that works with parallel make but not with phony dependencies is the following:
data.c data.h: data.foo
foo data.foo
data.h: data.c
The above rules are equivalent to
data.c: data.foo
foo data.foo
data.h: data.foo data.c
foo data.foo
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therefore a parallel make will have to serialize the builds of ‘data.c’ and ‘data.h’, and will
detect that the second is no longer needed once the first is over.
Using this pattern is probably enough for most cases. However it does not scale easily to
more output files (in this scheme all output files must be totally ordered by the dependency
relation), so we will explore a more complicated solution.
Another idea is to write the following:
# There is still a problem with this one.
data.c: data.foo
foo data.foo
data.h: data.c
The idea is that ‘foo data.foo’ is run only when ‘data.c’ needs to be updated, but we
further state that ‘data.h’ depends upon ‘data.c’. That way, if ‘data.h’ is required and
‘data.foo’ is out of date, the dependency on ‘data.c’ will trigger the build.
This is almost perfect, but suppose we have built ‘data.h’ and ‘data.c’, and then we
erase ‘data.h’. Then, running ‘make data.h’ will not rebuild ‘data.h’. The above rules
just state that ‘data.c’ must be up-to-date with respect to ‘data.foo’, and this is already
the case.
What we need is a rule that forces a rebuild when ‘data.h’ is missing. Here it is:
data.c: data.foo
foo data.foo
data.h: data.c
## Recover from the removal of $@
@if test -f $@; then :; else \
rm -f data.c; \
$(MAKE) $(AM_MAKEFLAGS) data.c; \
fi
The above scheme can be extended to handle more outputs and more inputs. One of the
outputs is selected to serve as a witness to the successful completion of the command, it
depends upon all inputs, and all other outputs depend upon it. For instance, if foo should
additionally read ‘data.bar’ and also produce ‘data.w’ and ‘data.x’, we would write:
data.c: data.foo data.bar
foo data.foo data.bar
data.h data.w data.x: data.c
## Recover from the removal of $@
@if test -f $@; then :; else \
rm -f data.c; \
$(MAKE) $(AM_MAKEFLAGS) data.c; \
fi
However there are now two minor problems in this setup. One is related to the timestamp
ordering of ‘data.h’, ‘data.w’, ‘data.x’, and ‘data.c’. The other one is a race condition if
a parallel make attempts to run multiple instances of the recover block at once.
Let us deal with the first problem. foo outputs four files, but we do not know in which
order these files are created. Suppose that ‘data.h’ is created before ‘data.c’. Then we
have a weird situation. The next time make is run, ‘data.h’ will appear older than ‘data.c’,
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the second rule will be triggered, a shell will be started to execute the ‘if...fi’ command,
but actually it will just execute the then branch, that is: nothing. In other words, because
the witness we selected is not the first file created by foo, make will start a shell to do
nothing each time it is run.
A simple riposte is to fix the timestamps when this happens.
data.c: data.foo data.bar
foo data.foo data.bar
data.h data.w data.x: data.c
@if test -f $@; then \
touch $@; \
else \
## Recover from the removal of $@
rm -f data.c; \
$(MAKE) $(AM_MAKEFLAGS) data.c; \
fi
Another solution is to use a different and dedicated file as witness, rather than using
any of foo’s outputs.
data.stamp: data.foo data.bar
@rm -f data.tmp
@touch data.tmp
foo data.foo data.bar
@mv -f data.tmp $@
data.c data.h data.w data.x: data.stamp
## Recover from the removal of $@
@if test -f $@; then :; else \
rm -f data.stamp; \
$(MAKE) $(AM_MAKEFLAGS) data.stamp; \
fi
‘data.tmp’ is created before foo is run, so it has a timestamp older than output files
output by foo. It is then renamed to ‘data.stamp’ after foo has run, because we do not
want to update ‘data.stamp’ if foo fails.
This solution still suffers from the second problem: the race condition in the recover
rule. If, after a successful build, a user erases ‘data.c’ and ‘data.h’, and runs ‘make
-j’, then make may start both recover rules in parallel. If the two instances of the rule
execute ‘$(MAKE) $(AM_MAKEFLAGS) data.stamp’ concurrently the build is likely to fail (for
instance, the two rules will create ‘data.tmp’, but only one can rename it).
Admittedly, such a weird situation does not arise during ordinary builds. It occurs only
when the build tree is mutilated. Here ‘data.c’ and ‘data.h’ have been explicitly removed
without also removing ‘data.stamp’ and the other output files. make clean; make will
always recover from these situations even with parallel makes, so you may decide that the
recover rule is solely to help non-parallel make users and leave things as-is. Fixing this
requires some locking mechanism to ensure only one instance of the recover rule rebuilds
‘data.stamp’. One could imagine something along the following lines.
data.c data.h data.w data.x: data.stamp
## Recover from the removal of $@
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##
##
##
##
103
@if test -f $@; then :; else \
trap ’rm -rf data.lock data.stamp 1 2 13 15; \
mkdir is a portable test-and-set
if mkdir data.lock 2>/dev/null; then \
This code is being executed by the first process.
rm -f data.stamp; \
$(MAKE) $(AM_MAKEFLAGS) data.stamp; \
else \
This code is being executed by the follower processes.
Wait until the first process is done.
while test -d data.lock; do sleep 1; done; \
Succeed if and only if the first process succeeded.
test -f data.stamp; exit $$?; \
fi; \
fi
Using a dedicated witness, like ‘data.stamp’, is very handy when the list of output files
is not known beforehand. As an illustration, consider the following rules to compile many
‘*.el’ files into ‘*.elc’ files in a single command. It does not matter how ELFILES is defined
(as long as it is not empty: empty targets are not accepted by POSIX).
ELFILES = one.el two.el three.el ...
ELCFILES = $(ELFILES:=c)
elc-stamp: $(ELFILES)
@rm -f elc-temp
@touch elc-temp
$(elisp_comp) $(ELFILES)
@mv -f elc-temp $@
$(ELCFILES): elc-stamp
## Recover from the removal of $@
@if test -f $@; then :; else \
trap ’rm -rf elc-lock elc-stamp’ 1 2 13 15; \
if mkdir elc-lock 2>/dev/null; then \
## This code is being executed by the first process.
rm -f elc-stamp; \
$(MAKE) $(AM_MAKEFLAGS) elc-stamp; \
rmdir elc-lock; \
else \
## This code is being executed by the follower processes.
## Wait until the first process is done.
while test -d elc-lock; do sleep 1; done; \
## Succeed if and only if the first process succeeded.
test -f elc-stamp; exit $$?; \
fi; \
fi
Chapter 26: Frequently Asked Questions about Automake
104
For completeness it should be noted that GNU make is able to express rules with multiple
output files using pattern rules (see section “Pattern Rule Examples” in The GNU Make
Manual). We do not discuss pattern rules here because they are not portable, but they can
be convenient in packages that assume GNU make.
26.9 Installing to Hard-Coded Locations
My package needs to install some configuration file. I tried to use
the following rule, but ‘make distcheck’ fails. Why?
# Do not do this.
install-data-local:
$(INSTALL_DATA) $(srcdir)/afile $(DESTDIR)/etc/afile
My package needs to populate the installation directory of another
package at install-time. I can easily compute that installation
directory in ‘configure’, but if I install files therein,
‘make distcheck’ fails. How else should I do?
These two setups share their symptoms: ‘make distcheck’ fails because they are installing files to hard-coded paths. In the later case the path is not really hard-coded in
the package, but we can consider it to be hard-coded in the system (or in whichever tool
that supplies the path). As long as the path does not use any of the standard directory
variables (‘$(prefix)’, ‘$(bindir)’, ‘$(datadir)’, etc.), the effect will be the same: userinstallations are impossible.
When a (non-root) user wants to install a package, he usually has no right to install
anything in ‘/usr’ or ‘/usr/local’. So he does something like ‘./configure --prefix
~/usr’ to install package in his own ‘~/usr’ tree.
If a package attempts to install something to some hard-coded path (e.g., ‘/etc/afile’),
regardless of this ‘--prefix’ setting, then the installation will fail. ‘make distcheck’ performs such a ‘--prefix’ installation, hence it will fail too.
Now, there are some easy solutions.
The above install-data-local example for installing ‘/etc/afile’ would be better
replaced by
sysconf_DATA = afile
by default sysconfdir will be ‘$(prefix)/etc’, because this is what the GNU Standards
require. When such a package is installed on a FHS compliant system, the installer will
have to set ‘--sysconfdir=/etc’. As the maintainer of the package you should not be
concerned by such site policies: use the appropriate standard directory variable to install
your files so that installer can easily redefine these variables to match their site conventions.
Installing files that should be used by another package, is slightly more involved. Let’s
take an example and assume you want to install shared library that is a Python extension
module. If you ask Python where to install the library, it will answer something like this:
% python -c ’from distutils import sysconfig;
print sysconfig.get_python_lib(1,0)’
/usr/lib/python2.3/site-packages
Chapter 27: History of Automake
105
If you indeed use this absolute path to install your shared library, non-root users will
not be able to install the package, hence distcheck fails.
Let’s do better. The ‘sysconfig.get_python_lib()’ function actually accepts a third
argument that will replace Python’s installation prefix.
% python -c ’from distutils import sysconfig;
print sysconfig.get_python_lib(1,0,"${exec_prefix}")’
${exec_prefix}/lib/python2.3/site-packages
You can also use this new path. If you do
• root users can install your package with the same ‘--prefix’ as Python (you get the
behavior of the previous attempt)
• non-root users can install your package too, they will have the extension module in a
place that is not searched by Python but they can work around this using environment
variables (and if you installed scripts that use this shared library, it’s easy to tell Python
were to look in the beginning of your script, so the script works in both cases).
The AM_PATH_PYTHON macro uses similar commands to define ‘$(pythondir)’ and
‘$(pyexecdir)’ (see Section 9.5 [Python], page 64).
Of course not all tools are as advanced as Python regarding that substitution of prefix.
So another strategy is to figure the part of the of the installation directory that must
be preserved. For instance, here is how AM_PATH_LISPDIR (see Section 9.1 [Emacs Lisp],
page 62) computes ‘$(lispdir)’:
$EMACS -batch -q -eval ’(while load-path
(princ (concat (car load-path) "\n"))
(setq load-path (cdr load-path)))’ >conftest.out
lispdir=‘sed -n
-e ’s,/$,,’
-e ’/.*\/lib\/x*emacs\/site-lisp$/{
s,.*/lib/\(x*emacs/site-lisp\)$,${libdir}/\1,;p;q;
}’
-e ’/.*\/share\/x*emacs\/site-lisp$/{
s,.*/share/\(x*emacs/site-lisp\),${datadir}/\1,;p;q;
}’
conftest.out‘
I.e., it just picks the first directory that looks like ‘*/lib/*emacs/site-lisp’
or ‘*/share/*emacs/site-lisp’ in the search path of emacs, and then substitutes
‘${libdir}’ or ‘${datadir}’ appropriately.
The emacs case looks complicated because it processes a list and expect two possible
layouts, otherwise it’s easy, and the benefit for non-root users are really worth the extra
sed invocation.
27 History of Automake
This chapter presents various aspects of the history of Automake. The exhausted reader
can safely skip it; this will be more of interest to nostalgic people, or to those curious to
learn about the evolution of Automake.
Chapter 27: History of Automake
106
27.1 Timeline
1994-09-19 First CVS commit.
If we can trust the CVS repository, David J. MacKenzie (djm) started working
on Automake (or AutoMake, as it was spelt then) this Monday.
The first version of the automake script looks as follows.
#!/bin/sh
status=0
for makefile
do
if test ! -f ${makefile}.am; then
echo "automake: ${makefile}.am: No such honkin’ file"
status=1
continue
fi
exec 4> ${makefile}.in
done
From this you can already see that Automake will be about reading ‘*.am’ file
and producing ‘*.in’ files. You cannot see anything else, but if you also know
that David is the one who created Autoconf two years before you can guess the
rest.
Several commits follow, and by the end of the day Automake is reported to
work for GNU fileutils and GNU m4.
The modus operandi is the one that is still used today: variables assignments
in ‘Makefile.am’ files trigger injections of precanned ‘Makefile’ fragments into
the generated ‘Makefile.in’. The use of ‘Makefile’ fragments was inspired by
the 4.4BSD make and include files, however Automake aims to be portable and
to conform to the GNU standards for ‘Makefile’ variables and targets.
At this point, the most recent release of Autoconf is version 1.11, and David is
preparing to release Autoconf 2.0 in late October. As a matter of fact, he will
barely touch Automake after September.
1994-11-05 David MacKenzie’s last commit.
At this point Automake is a 200 line portable shell script, plus 332 lines of
‘Makefile’ fragments. In the ‘README’, David states his ambivalence between
“portable shell” and “more appropriate language”:
I wrote it keeping in mind the possibility of it becoming an Autoconf macro, so it would run at configure-time. That would slow
configuration down a bit, but allow users to modify the Makefile.am
without needing to fetch the AutoMake package. And, the Makefile.in files wouldn’t need to be distributed. But all of AutoMake
would. So I might reimplement AutoMake in Perl, m4, or some
other more appropriate language.
Chapter 27: History of Automake
107
Automake is described as “an experimental Makefile generator”. There is no
documentation. Adventurous users are referred to the examples and patches
needed to use Automake with GNU m4 1.3, fileutils 3.9, time 1.6, and development versions of find and indent.
These examples seem to have been lost. However at the time of writing (10
years later in September, 2004) the FSF still distributes a package that uses
this version of Automake: check out GNU termutils 2.0.
1995-11-12 Tom Tromey’s first commit.
After one year of inactivity, Tom Tromey takes over the package. Tom was
working on GNU cpio back then, and doing this just for fun, having trouble
finding a project to contribute to. So while hacking he wanted to bring the
‘Makefile.in’ up to GNU standards. This was hard, and one day he saw
Automake on ftp://alpha.gnu.org/, grabbed it and tried it out.
Tom didn’t talk to djm about it until later, just to make sure he didn’t mind if
he made a release. He did a bunch of early releases to the Gnits folks.
Gnits was (and still is) totally informal, just a few GNU friends who François
Pinard knew, who were all interested in making a common infrastructure for
GNU projects, and shared a similar outlook on how to do it. So they were able
to make some progress. It came along with Autoconf and extensions thereof,
and then Automake from David and Tom (who were both gnitsians). One of
their ideas was to write a document paralleling the GNU standards, that was
more strict in some ways and more detailed. They never finished the GNITS
standards, but the ideas mostly made their way into Automake.
1995-11-23 Automake 0.20
Besides introducing automatic dependency tracking (see Section 27.2 [Dependency Tracking Evolution], page 117), this version also supplies a 9-page manual.
At this time aclocal and AM_INIT_AUTOMAKE did not exist, so many things
had to be done by hand. For instance, here is what a configure.in (this is the
former name of the ‘configure.ac’ we use today) must contain in order to use
Automake 0.20:
PACKAGE=cpio
VERSION=2.3.911
AC_DEFINE_UNQUOTED(PACKAGE, "$PACKAGE")
AC_DEFINE_UNQUOTED(VERSION, "$VERSION")
AC_SUBST(PACKAGE)
AC_SUBST(VERSION)
AC_ARG_PROGRAM
AC_PROG_INSTALL
(Today all of the above is achieved by AC_INIT and AM_INIT_AUTOMAKE.)
Here is how programs are specified in ‘Makefile.am’:
PROGRAMS = hello
hello_SOURCES = hello.c
This looks pretty much like what we do today, except the PROGRAMS variable has
no directory prefix specifying where ‘hello’ should be installed: all programs
Chapter 27: History of Automake
108
are installed in ‘$(bindir)’. LIBPROGRAMS can be used to specify programs
that must be built but not installed (it is called noinst_PROGRAMS nowadays).
Programs can be built conditionally using AC_SUBSTitutions:
PROGRAMS = @progs@
AM_PROGRAMS = foo bar baz
(AM_PROGRAMS has since then been renamed to EXTRA_PROGRAMS.)
Similarly scripts, static libraries, and data can built and installed using the
LIBRARIES, SCRIPTS, and DATA variables. However LIBRARIES were treated
a bit specially in that Automake did automatically supply the ‘lib’ and ‘.a’
prefixes. Therefore to build ‘libcpio.a’, one had to write
LIBRARIES = cpio
cpio_SOURCES = ...
Extra files to distribute must be listed in DIST_OTHER (the ancestor of EXTRA_
DIST). Also extra directories that are to be distributed should appear in DIST_
SUBDIRS, but the manual describes this as a temporary ugly hack (today extra
directories should also be listed in EXTRA_DIST, and DIST_SUBDIRS is used for
another purpose, see Section 6.2 [Conditional Subdirectories], page 25).
1995-11-26 Automake 0.21
In less time that it takes to cook a frozen pizza, Tom rewrites Automake using
Perl. At this time Perl 5 is only one year old, and Perl 4.036 is in use at many
sites. Supporting several Perl versions has been a source of problems through
the whole history of Automake.
If you never used Perl 4, imagine Perl 5 without objects, without ‘my’ variables
(only dynamically scoped ‘local’ variables), without function prototypes, with
function calls that needs to be prefixed with ‘&’, etc. Traces of this old style
can still be found in today’s automake.
1995-11-28 Automake 0.22
1995-11-29 Automake 0.23
Bug fixes.
1995-12-08 Automake 0.24
1995-12-10 Automake 0.25
Releases are raining. 0.24 introduces the uniform naming scheme we use
today, i.e., bin_PROGRAMS instead of PROGRAMS, noinst_LIBRARIES instead
of LIBLIBRARIES, etc.
(However EXTRA_PROGRAMS does not exist yet,
AM_PROGRAMS is still in use; and TEXINFOS and MANS still have no directory
prefixes.) Adding support for prefixes like that was one of the major ideas in
automake; it has lasted pretty well.
AutoMake is renamed to Automake (Tom seems to recall it was François
Pinard’s doing).
0.25 fixes a Perl 4 portability bug.
Chapter 27: History of Automake
1995-12-18
1995-12-31
1996-01-03
1996-01-03
109
Jim Meyering starts using Automake in GNU Textutils.
François Pinard starts using Automake in GNU tar.
Automake 0.26
Automake 0.27
Of the many change and suggestions sent by François Pinard and included in
0.26, the most important is perhaps the advise that to ease customization a
user rule or variable definition should always override an Automake rule or
definition.
Gordon Matzigkeit and Jim Meyering are two other early contributors that
have been sending fixes.
0.27 fixes yet another Perl 4 portability bug.
1996-01-13 Automake 0.28
Automake starts scanning ‘configure.in’ for LIBOBJS support. This is an
important step because until this version Automake did only know about the
‘Makefile.am’s it processed. ‘configure.in’ was Autoconf’s world and the
link between Autoconf and Automake had to be done by the ‘Makefile.am’
author. For instance, if ‘config.h’ was generated by ‘configure’, it was the
package maintainer’s responsibility to define the CONFIG_HEADER variable in
each ‘Makefile.am’.
Succeeding releases will rely more and more on scanning ‘configure.in’ to
better automate the Autoconf integration.
0.28 also introduces the AUTOMAKE_OPTIONS variable and the ‘--gnu’ and
‘--gnits’ options, the latter being stricter.
1996-02-07 Automake 0.29
Thanks to ‘configure.in’ scanning, CONFIG_HEADER is gone, and rebuild rules
for ‘configure’-generated file are automatically output.
TEXINFOS and MANS converted to the uniform naming scheme.
1996-02-24 Automake 0.30
The test suite is born. It contains 9 tests. From now on test cases will be added
pretty regularly (see Section 27.3 [Releases], page 121), and this proved to be
really helpful later on.
EXTRA_PROGRAMS finally replaces AM_PROGRAMS.
All the third-party Autoconf macros, written mostly by François Pinard (and
later Jim Meyering), are distributed in Automake’s hand-written ‘aclocal.m4’
file. Package maintainers are expected to extract the necessary macros from this
file. (In previous version you had to copy and paste them from the manual...)
1996-03-11 Automake 0.31
The test suite in 0.30 was run via a long check-local rule. Upon Ulrich
Drepper’s suggestion, 0.31 makes it an Automake rule output whenever the
TESTS variable is defined.
DIST_OTHER is renamed to EXTRA_DIST, and the check_ prefix is introduced.
The syntax is now the same as today.
Chapter 27: History of Automake
110
1996-03-15 Gordon Matzigkeit starts writing libtool.
1996-04-27 Automake 0.32
-hook targets are introduced; an idea from Dieter Baron.
‘*.info’ files, which were output in the build directory are now built in the
source directory, because they are distributed. It seems these files like to move
back and forth as that will happen again in future versions.
1996-05-18 Automake 0.33
Gord Matzigkeit’s main two contributions:
• very preliminary libtool support
• the distcheck rule
Although they were very basic at this point, these are probably among the top
features for Automake today.
Jim Meyering also provides the infamous jm_MAINTAINER_MODE, since then renamed to AM_MAINTAINER_MODE and abandoned by its author (see Section 26.2
[maintainer-mode], page 92).
1996-05-28 Automake 1.0
After only six months of heavy development, the automake script is 3134 lines
long, plus 973 lines of ‘Makefile’ fragments. The package has 30 pages of
documentation, and 38 test cases. ‘aclocal.m4’ contains 4 macros.
From now on and until version 1.4, new releases will occur at a rate of about
one a year. 1.1 did not exist, actually 1.1b to 1.1p have been the name of beta
releases for 1.2. This is the first time Automake uses suffix letters to designate
beta releases, an habit that lasts.
1996-10-10 Kevin Dalley packages Automake 1.0 for Debian GNU/Linux.
1996-11-26 David J. MacKenzie releases Autoconf 2.12.
Between June and October, the Autoconf development is almost staled. Roland
McGrath has been working at the beginning of the year. David comes back in
November to release 2.12, but he won’t touch Autoconf anymore after this
year, and Autoconf then really stagnates. The desolate Autoconf ‘ChangeLog’
for 1997 lists only 7 commits.
1997-02-28 automake@gnu.ai.mit.edu list alive
The mailing list is announced as follows:
I’ve created the "automake" mailing list. It is
"automake@gnu.ai.mit.edu". Administrivia, as always, to
automake-request@gnu.ai.mit.edu.
The charter of this list is discussion of automake, autoconf, and
other configuration/portability tools (eg libtool). It is expected
that discussion will range from pleas for help all the way up to
patches.
This list is archived on the FSF machines. Offhand I don’t know if
you can get the archive without an account there.
This list is open to anybody who wants to join.
friends!
-- Tom Tromey
Tell all your
Chapter 27: History of Automake
111
Before that people were discussing Automake privately, on the Gnits mailing
list (which is not public either), and less frequently on gnu.misc.discuss.
gnu.ai.mit.edu is now gnu.org, in case you never noticed. The archives of the
early years of the automake@gnu.org list have been lost, so today it is almost
impossible to find traces of discussions that occurred before 1999. This has
been annoying more than once, as such discussions can be useful to understand
the rationale behind a piece of uncommented code that was introduced back
then.
1997-06-22 Automake 1.2
Automake developments continues, and more and more new Autoconf macros
are required. Distributing them in ‘aclocal.m4’ and requiring people to browse
this file to extract the relevant macros becomes uncomfortable. Ideally, some
of them should be contributed to Autoconf so that they can be used directly,
however Autoconf is currently inactive. Automake 1.2 consequently introduces
aclocal (aclocal was actually started on 1996-07-28), a tool that automatically constructs an ‘aclocal.m4’ file from a repository of third-party macros.
Because Autoconf has stalled, Automake also becomes a kind of repository for
such third-party macros, even macros completely unrelated to Automake (for
instance macros that fix broken Autoconf macros).
The 1.2 release contains 20 macros, among which the AM_INIT_AUTOMAKE macro
that simplifies the creation of ‘configure.in’.
Libtool is fully supported using *_LTLIBRARIES.
The missing script is introduced by François Pinard; it is meant to be a better solution than AM_MAINTAINER_MODE (see Section 26.2 [maintainer-mode],
page 92).
Conditionals support was implemented by Ian Lance Taylor. At the time, Tom
and Ian were working on an internal project at Cygnus. They were using
ILU, which is pretty similar to CORBA. They wanted to integrate ILU into
their build, which was all ‘configure’-based, and Ian thought that adding
conditionals to automake was simpler than doing all the work in ‘configure’
(which was the standard at the time). So this was actually funded by Cygnus.
This very useful but tricky feature will take a lot of time to stabilize. (At the
time this text is written, there are still primaries that have not been updated
to support conditional definitions in Automake 1.9.)
The automake script has almost doubled: 6089 lines of Perl, plus 1294 lines of
‘Makefile’ fragments.
1997-07-08 Gordon Matzigkeit releases Libtool 1.0.
1998-04-05 Automake 1.3
This is a small advance compared to 1.2. It add support for assembly, and
preliminary support for Java.
Perl 5.004 04 is out, but fixes to support Perl 4 are still regularly submitted
whenever Automake breaks it.
1998-09-06 sourceware.cygnus.com is on-line.
Sourceware was setup by Jason Molenda to host open source projects.
Chapter 27: History of Automake
112
1998-09-19 Automake CVS repository moved to sourceware.cygnus.com
1998-10-26 sourceware.cygnus.com announces it hosts Automake
Automake is now hosted on sourceware.cygnus.com. It has a publicly accessible CVS repository. This CVS repository is a copy of the one Tom was using
on his machine, which in turn is based on a copy of the CVS repository of David
MacKenzie. This is why we still have to full source history. (Automake is still
on Sourceware today, but the host has been renamed to sources.redhat.com.)
The oldest file in the administrative directory of the CVS repository that
was created on Sourceware is dated 1998-09-19, while the announcement that
automake and autoconf had joined sourceware was made on 1998-10-26. They
were among the first projects to be hosted there.
The heedful reader will have noticed Automake was exactly 4-year-old on 199809-19.
1999-01-05 Ben Elliston releases Autoconf 2.13.
1999-01-14 Automake 1.4
This release adds support for Fortran 77 and for the include statement. Also,
‘+=’ assignments are introduced, but it is still quite easy to fool Automake when
mixing this with conditionals.
These two releases, Automake 1.4 and Autoconf 2.13 makes a duo that will be
used together for years.
automake is 7228 lines, plus 1591 lines of Makefile fragment, 20 macros (some
1.3 macros were finally contributed back to Autoconf), 197 test cases, and 51
pages of documentation.
1999-03-27 The user-dep-branch is created on the CVS repository.
This implements a new dependency tracking schemed that should be able to
handle automatic dependency tracking using any compiler (not just gcc) and
any make (not just GNU make). In addition, the new scheme should be more
reliable than the old one, as dependencies are generated on the end user’s
machine. Alexandre Oliva creates depcomp for this purpose.
See Section 27.2 [Dependency Tracking Evolution], page 117, for more details
about the evolution of automatic dependency tracking in Automake.
1999-11-21 The user-dep-branch is merged into the main trunk.
This was a huge problem since we also had patches going in on the trunk. The
merge took a long time and was very painful.
2000-05-10
Since September 1999 and until 2003, Akim Demaille will be zealously revamping Autoconf.
I think the next release should be called "3.0".
Let’s face it: you’ve basically rewritten autoconf.
Every weekend there are 30 new patches.
I don’t see how we could call this "2.15" with a straight face.
– Tom Tromey on autoconf@gnu.org
Chapter 27: History of Automake
113
Actually Akim works like a submarine: he will pile up patches while he works
off-line during the weekend, and flush them in batch when he resurfaces on
Monday.
2001-01-24
On this Wednesday, Autoconf 2.49c, the last beta before Autoconf 2.50 is out,
and Akim has to find something to do during his week-end :)
2001-01-28
Akim sends a batch of 14 patches to automake@gnu.org.
Aiieeee! I was dreading the day that the Demaillator turned his
sights on automake. . . and now it has arrived! – Tom Tromey
It’s only the beginning: in two months he will send 192 patches. Then he would
slow down so Tom can catch up and review all this. Initially Tom actually read
all these patches, then he probably trustingly answered OK to most of them,
and finally gave up and let Akim apply whatever he wanted. There was no way
to keep up with that patch rate.
Anyway the patch below won’t apply since it predates Akim’s
sourcequake; I have yet to figure where the relevant passage has
been moved :) – Alexandre Duret-Lutz
All these patches were sent to and discussed on automake@gnu.org, so
subscribed users were literally drown in technical mails. Eventually, the
automake-patches@gnu.org mailing list was created in May.
Year after year, Automake had drifted away from its initial design: construct
‘Makefile.in’ by assembling various ‘Makefile’ fragments. In 1.4, lots of
‘Makefile’ rules are being emitted at various places in the automake script
itself; this does not help ensuring a consistent treatment of these rules (for
instance making sure that user-defined rules override Automake’s own rules).
One of Akim’s goal was moving all these hard-coded rules to separate ‘Makefile’
fragments, so the logic could be centralized in a ‘Makefile’ fragment processor.
Another significant contribution of Akim is the interface with the “trace” feature of Autoconf. The way to scan ‘configure.in’ at this time was to read the
file and grep the various macro of interest to Automake. Doing so could break
in many unexpected ways; automake could miss some definition (for instance
‘AC_SUBST([$1], [$2])’ where the arguments are known only when M4 is run),
or conversely it could detect some macro that was not expanded (because it is
called conditionally). In the CVS version of Autoconf, Akim had implemented
the ‘--trace’ option, which provides accurate information about where macros
are actually called and with what arguments. Akim will equip Automake with
a second ‘configure.in’ scanner that uses this ‘--trace’ interface. Since it
was not sensible to drop the Autoconf 2.13 compatibility yet, this experimental
scanner was only used when an environment variable was set, the traditional
grep-scanner being still the default.
2001-04-25 Gary V. Vaughan releases Libtool 1.4
It has been more than two years since Automake 1.4, CVS Automake has
suffered lot’s of heavy changes and still is not ready for release. Libtool 1.4
had to be distributed with a patch against Automake 1.4.
Chapter 27: History of Automake
114
2001-05-08 Automake 1.4-p1
2001-05-24 Automake 1.4-p2
Gary V. Vaughan, the principal Libtool maintainer, makes a “patch release” of
Automake:
The main purpose of this release is to have a stable automake which
is compatible with the latest stable libtool.
The release also contains obvious fixes for bugs in Automake 1.4, some of which
were reported almost monthly.
2001-05-21
2001-06-07
2001-06-10
2001-07-15
Akim Demaille releases Autoconf 2.50
Automake 1.4-p3
Automake 1.4-p4
Automake 1.4-p5
Gary continues his patch-release series. These also add support for some new
Autoconf 2.50 idioms. Essentially, Autoconf now advocates ‘configure.ac’
over ‘configure.in’, and it introduces a new syntax for AC_OUTPUTing files.
2001-08-23 Automake 1.5
A major and long-awaited release, that comes more than two years after 1.4.
It brings many changes, among which:
• The new dependency tracking scheme that uses depcomp. Aside from the
improvement on the dependency tracking itself (see Section 27.2 [Dependency Tracking Evolution], page 117), this also streamlines the use of automake generated ‘Makefile.in’s as the ‘Makefile.in’s used during development are now the same as those used in distributions. Before that the
‘Makefile.in’s generated for maintainers required GNU make and GCC,
they were different from the portable ‘Makefile’ generated for distribution;
this was causing some confusion.
• Support for per-target compilation flags.
• Support for reference to files in subdirectories in most ‘Makefile.am’ variables.
• Introduction of the dist_, nodist_, and nobase_ prefixes.
• Perl 4 support is finally dropped.
1.5 did broke several packages that worked with 1.4. Enough so that Linux distributions could not easily install the new Automake version without breaking
many of the packages for which they had to run automake.
Some of these breakages were effectively bugs that would eventually be fixed in
the next release. However, a lot of damage was caused by some changes made
deliberately to render Automake stricter on some setup we did consider bogus.
For instance, ‘make distcheck’ was improved to check that ‘make uninstall’
did remove all the files ‘make install’ installed, that ‘make distclean’ did
not omit some file, and that a VPATH build would work even if the source
directory was read-only. Similarly, Automake now rejects multiple definitions
of the same variable (because that would mix very badly with conditionals),
and ‘+=’ assignments with no previous definition. Because these changes all
Chapter 27: History of Automake
115
occurred suddenly after 1.4 had been established for more that two years, it
hurt users.
To make matter worse, meanwhile Autoconf (now at version 2.52) was facing
similar troubles, for similar reasons.
2002-03-05 Automake 1.6
This release introduced versioned installation (see Chapter 24 [API versioning],
page 88). This was mainly pushed by Havoc Pennington, taking the GNOME
source tree as motive: due to incompatibilities between the autotools it’s impossible for the GNOME packages to switch to Autoconf 2.53 and Automake
1.5 all at once, so they are currently stuck with Autoconf 2.13 and Automake
1.4.
The idea was to call this version ‘automake-1.6’, call all its bug-fix versions
identically, and switch to ‘automake-1.7’ for the next release that adds new features or changes some rules. This scheme implies maintaining a bug-fix branch
in addition to the development trunk, which means more work from the maintainer, but providing regular bug-fix releases proved to be really worthwhile.
Like 1.5, 1.6 also introduced a bunch of incompatibilities, meant or not. Perhaps
the more annoying was the dependence on the newly released Autoconf 2.53.
Autoconf seemed to have stabilized enough since its explosive 2.50 release, and
included changes required to fix some bugs in Automake. In order to upgrade
to Automake 1.6, people now had to upgrade Autoconf too; for some packages
it was no picnic.
While versioned installation helped people to upgrade, it also unfortunately
allowed people not to upgrade. At the time of writing, some Linux distributions
are shipping packages for Automake 1.4, 1.5, 1.6, 1.7, 1.8, and 1.9. Most of these
still install 1.4 by default. Some distribution also call 1.4 the “stable” version,
and present “1.9” as the development version; this does not really makes sense
since 1.9 is way more solid than 1.4. All this does not help the newcomer.
2002-04-11 Automake 1.6.1
1.6, and the upcoming 1.4-p6 release were the last release by Tom. This one and
those following will be handled by Alexandre Duret-Lutz. Tom is still around,
and will be there until about 1.7, but his interest into Automake is drifting
away towards projects like gcj.
Alexandre has been using Automake since 2000, and started to contribute
mostly on Akim’s incitement (Akim and Alexandre have been working in the
same room from 1999 to 2002). In 2001 and 2002 he had a lot of free time to
enjoy hacking Automake.
2002-06-14 Automake 1.6.2
2002-07-28 Automake 1.6.3
2002-07-28 Automake 1.4-p6
Two releases on the same day. 1.6.3 is a bug-fix release.
Tom Tromey backported the versioned installation mechanism on the 1.4
branch, so that Automake 1.6.x and Automake 1.4-p6 could be installed side
by side. Another request from the GNOME folks.
Chapter 27: History of Automake
116
2002-09-25 Automake 1.7
This release switches to the new ‘configure.ac’ scanner Akim was experimenting in 1.5.
2002-10-16
2002-12-06
2003-02-20
2003-04-23
2003-05-18
2003-07-10
2003-09-07
2003-10-07
Automake 1.7.1
Automake 1.7.2
Automake 1.7.3
Automake 1.7.4
Automake 1.7.5
Automake 1.7.6
Automake 1.7.7
Automake 1.7.8
Many bug-fix releases. 1.7 lasted because the development version (upcoming
1.8) was suffering some major internal revamping.
2003-10-26 Automake on screen
Episode 49, ‘Repercussions’, in the third season of the ‘Alias’ TV show is first
aired.
Marshall, one of the character, is working on a computer virus that he has
to modify before it gets into the wrong hands or something like that. The
screenshots you see do not show any program code, they show a ‘Makefile.in’
generated by automake...
2003-11-09 Automake 1.7.9
2003-12-10 Automake 1.8
The most striking update is probably that of aclocal.
aclocal now uses m4_include in the produced aclocal.m4 when the included
macros are already distributed with the package (an idiom used in many packages), which reduces code duplication. Many people liked that, but in fact this
change was really introduced to fix a bug in rebuild rules: ‘Makefile.in’ must
be rebuilt whenever a dependency of ‘configure’ changes, but all the ‘m4’ files
included in ‘aclocal.m4’ where unknown from automake. Now automake can
just trace the m4_includes to discover the dependencies.
aclocal also starts using the ‘--trace’ Autoconf option in order to discover
used macros more accurately. This will turn out to be very tricky (later releases
will improve this) as people had devised many ways to cope with the limitation of previous aclocal versions, notably using handwritten m4_includes:
aclocal must make sure not to redefine a rule that is already included by such
statement.
Automake also has seen its guts rewritten. Although this rewriting took a lot
of efforts, it is only apparent to the users in that some constructions previously
disallowed by the implementation now work nicely. Conditionals, Locations,
Chapter 27: History of Automake
2004-01-11
2004-01-12
2004-03-07
2004-04-25
2004-05-16
2004-07-28
2004-08-11
2004-09-19
117
Variable and Rule definitions, Options: these items on which Automake works
have been rewritten as separate Perl modules, and documented.
Automake 1.8.1
Automake 1.8.2
Automake 1.8.3
Automake 1.8.4
Automake 1.8.5
Automake 1.9
This release tries to simplify the compilation rules it outputs to reduce the size
of the Makefile. The complaint initially come from the libgcj developers. Their
‘Makefile.in’ generated with Automake 1.4 and custom build rules (1.4 did
not support compiled Java) is 250KB. The one generated by 1.8 was over 9MB!
1.9 gets it down to 1.2MB.
Aside from this it contains mainly minor changes and bug-fixes.
Automake 1.9.1
Automake 1.9.2
Automake has ten years. This chapter of the manual was initially written for
this occasion.
27.2 Dependency Tracking in Automake
Over the years Automake has deployed three different dependency tracking methods. Each
method, including the current one, has had flaws of various sorts. Here we lay out the
different dependency tracking methods, their flaws, and their fixes. We conclude with recommendations for tool writers, and by indicating future directions for dependency tracking
work in Automake.
27.2.1 First Take
Description
Our first attempt at automatic dependency tracking was based on the method recommended
by GNU make. (see section “Generating Prerequisites Automatically” in The GNU make
Manual)
This version worked by precomputing dependencies ahead of time. For each source file,
it had a special ‘.P’ file that held the dependencies. There was a rule to generate a ‘.P’ file
by invoking the compiler appropriately. All such ‘.P’ files were included by the ‘Makefile’,
thus implicitly becoming dependencies of ‘Makefile’.
Bugs
This approach had several critical bugs.
• The code to generate the ‘.P’ file relied on gcc. (A limitation, not technically a bug.)
• The dependency tracking mechanism itself relied on GNU make. (A limitation, not
technically a bug.)
• Because each ‘.P’ file was a dependency of ‘Makefile’, this meant that dependency
tracking was done eagerly by make. For instance, ‘make clean’ would cause all the
dependency files to be updated, and then immediately removed. This eagerness also
Chapter 27: History of Automake
118
caused problems with some configurations; if a certain source file could not be compiled
on a given architecture for some reason, dependency tracking would fail, aborting the
entire build.
• As dependency tracking was done as a pre-pass, compile times were doubled–the compiler had to be run twice per source file.
• ‘make dist’ re-ran automake to generate a ‘Makefile’ that did not have automatic
dependency tracking (and that was thus portable to any version of make). In order to
do this portably, Automake had to scan the dependency files and remove any reference
that was to a source file not in the distribution. This process was error-prone. Also, if
‘make dist’ was run in an environment where some object file had a dependency on a
source file that was only conditionally created, Automake would generate a ‘Makefile’
that referred to a file that might not appear in the end user’s build. A special, hacky
mechanism was required to work around this.
Historical Note
The code generated by Automake is often inspired by the ‘Makefile’ style of a particular
author. In the case of the first implementation of dependency tracking, I believe the impetus
and inspiration was Jim Meyering. (I could be mistaken. If you know otherwise feel free to
correct me.)
27.2.2 Dependencies As Side Effects
Description
The next refinement of Automake’s automatic dependency tracking scheme was to implement dependencies as side effects of the compilation. This was aimed at solving the most
commonly reported problems with the first approach. In particular we were most concerned
with eliminating the weird rebuilding effect associated with make clean.
In this approach, the ‘.P’ files were included using the -include command, which let us
create these files lazily. This avoided the ‘make clean’ problem.
We only computed dependencies when a file was actually compiled. This avoided the
performance penalty associated with scanning each file twice. It also let us avoid the other
problems associated with the first, eager, implementation. For instance, dependencies would
never be generated for a source file that was not compilable on a given architecture (because
it in fact would never be compiled).
Bugs
• This approach also relied on the existence of gcc and GNU make. (A limitation, not
technically a bug.)
• Dependency tracking was still done by the developer, so the problems from the first
implementation relating to massaging of dependencies by ‘make dist’ were still in effect.
• This implementation suffered from the “deleted header file” problem. Suppose a lazilycreated ‘.P’ file includes a dependency on a given header file, like this:
maude.o: maude.c something.h
Chapter 27: History of Automake
119
Now suppose that the developer removes ‘something.h’ and updates ‘maude.c’ so that
this include is no longer needed. If he runs make, he will get an error because there is
no way to create ‘something.h’.
We fixed this problem in a later release by further massaging the output of gcc to
include a dummy dependency for each header file.
27.2.3 Dependencies for the User
Description
The bugs associated with ‘make dist’, over time, became a real problem. Packages using
Automake were being built on a large number of platforms, and were becoming increasingly
complex. Broken dependencies were distributed in “portable” ‘Makefile.in’s, leading to
user complaints. Also, the requirement for gcc and GNU make was a constant source of bug
reports. The next implementation of dependency tracking aimed to remove these problems.
We realized that the only truly reliable way to automatically track dependencies was
to do it when the package itself was built. This meant discovering a method portable
to any version of make and any compiler. Also, we wanted to preserve what we saw as
the best point of the second implementation: dependency computation as a side effect of
compilation.
In the end we found that most modern make implementations support some form of
include directive. Also, we wrote a wrapper script that let us abstract away differences
between dependency tracking methods for compilers. For instance, some compilers cannot
generate dependencies as a side effect of compilation. In this case we simply have the
script run the compiler twice. Currently our wrapper script (depcomp) knows about twelve
different compilers (including a "compiler" that simply invokes makedepend and then the
real compiler, which is assumed to be a standard Unix-like C compiler with no way to do
dependency tracking).
Bugs
• Running a wrapper script for each compilation slows down the build.
• Many users don’t really care about precise dependencies.
• This implementation, like every other automatic dependency tracking scheme in common use today (indeed, every one we’ve ever heard of), suffers from the “duplicated
new header” bug.
This bug occurs because dependency tracking tools, such as the compiler, only generate
dependencies on the successful opening of a file, and not on every probe.
Suppose for instance that the compiler searches three directories for a given header, and
that the header is found in the third directory. If the programmer erroneously adds a
header file with the same name to the first directory, then a clean rebuild from scratch
could fail (suppose the new header file is buggy), whereas an incremental rebuild will
succeed.
What has happened here is that people have a misunderstanding of what a dependency
is. Tool writers think a dependency encodes information about which files were read
by the compiler. However, a dependency must actually encode information about what
the compiler tried to do.
Chapter 27: History of Automake
120
This problem is not serious in practice. Programmers typically do not use the same
name for a header file twice in a given project. (At least, not in C or C++. This
problem may be more troublesome in Java.) This problem is easy to fix, by modifying
dependency generators to record every probe, instead of every successful open.
• Since automake generates dependencies as a side effect of compilation, there is a bootstrapping problem when header files are generated by running a program. The problem
is that, the first time the build is done, there is no way by default to know that the
headers are required, so make might try to run a compilation for which the headers
have not yet been built.
This was also a problem in the previous dependency tracking implementation.
The current fix is to use BUILT_SOURCES to list built headers (see Section 8.4 [Sources],
page 58). This causes them to be built before any other other build rules are run. This
is unsatisfactory as a general solution, however in practice it seems sufficient for most
actual programs.
This code is used since Automake 1.5.
In GCC 3.0, we managed to convince the maintainers to add special command-line
options to help Automake more efficiently do its job. We hoped this would let us avoid the
use of a wrapper script when Automake’s automatic dependency tracking was used with
gcc.
Unfortunately, this code doesn’t quite do what we want. In particular, it removes the
dependency file if the compilation fails; we’d prefer that it instead only touch the file in any
way if the compilation succeeds.
Nevertheless, since Automake 1.7, when a recent gcc is detected at configure time, we
inline the dependency-generation code and do not use the depcomp wrapper script. This
makes compilations faster for those using this compiler (probably our primary user base).
The counterpart is that because we have to encode two compilation rules in ‘Makefile’
(with or without depcomp), the produced ‘Makefile’s are larger.
27.2.4 Techniques for Computing Dependencies
There are actually several ways for a build tool like Automake to cause tools to generate
dependencies.
makedepend
This was a commonly-used method in the past. The idea is to run a special
program over the source and have it generate dependency information. Traditional implementations of makedepend ere not completely precise; ordinarily
they were conservative and discovered too many dependencies.
The tool
An obvious way to generate dependencies is to simply write the tool so that it
can generate the information needed by the build tool. This is also the most
portable method. Many compilers have an option to generate dependencies.
Unfortunately, not all tools provide such an option.
The file system
It is possible to write a special file system that tracks opens, reads, writes, etc,
and then feed this information back to the build tool. clearmake does this.
This is a very powerful technique, as it doesn’t require cooperation from the
Chapter 27: History of Automake
121
tool. Unfortunately it is also very difficult to implement and also not practical
in the general case.
LD_PRELOAD
Rather than use the file system, one could write a special library to intercept
open and other syscalls. This technique is also quite powerful, but unfortunately
it is not portable enough for use in automake.
27.2.5 Recommendations for Tool Writers
We think that every compilation tool ought to be able to generate dependencies as a side
effect of compilation. Furthermore, at least while make-based tools are nearly universally
in use (at least in the free software community), the tool itself should generate dummy
dependencies for header files, to avoid the deleted header file bug. Finally, the tool should
generate a dependency for each probe, instead of each successful file open, in order to avoid
the duplicated new header bug.
27.2.6 Future Directions for Automake’s Dependency Tracking
Currently, only languages and compilers understood by Automake can have dependency
tracking enabled. We would like to see if it is practical (and worthwhile) to let this support
be extended by the user to languages unknown to Automake.
27.3 Release Statistics
The following table (inspired by ‘perlhist(1)’) quantifies the evolution of Automake using
these metrics:
Date, Rel
The date and version of the release.
am
The number of lines of the automake script.
acl
The number of lines of the aclocal script.
pm
The number of lines of the Perl supporting modules.
‘*.am’
The number of lines of the ‘Makefile’ fragments. The number in parenthesis
is the number of files.
m4
The number of lines (and files) of Autoconf macros.
doc
The number of pages of the documentation (the Postscript version).
t
The number of test cases in the test suite.
Date
1994-09-19
1994-11-05
1995-11-23
1995-11-26
1995-11-28
1995-11-29
1995-12-08
1995-12-10
Rel
CVS
CVS
0.20
0.21
0.22
0.23
0.24
0.25
am
141
208
533
613
1116
1240
1462
1513
acl
pm
‘*.am’
299 (24)
332 (28)
458 (35)
480 (36)
539 (38)
541 (38)
504 (33)
511 (37)
m4
doc
9
11
12
12
14
15
t
Chapter 27: History of Automake
1996-01-03
1996-01-03
1996-01-13
1996-02-07
1996-02-24
1996-03-11
1996-04-27
1996-05-18
1996-05-28
1997-06-22
1998-04-05
1999-01-14
2001-05-08
2001-05-24
2001-06-07
2001-06-10
2001-07-15
2001-08-23
2002-03-05
2002-04-11
2002-06-14
2002-07-28
2002-07-28
2002-09-25
2002-10-16
2002-12-06
2003-02-20
2003-04-23
2003-05-18
2003-07-10
2003-09-07
2003-10-07
2003-11-09
2003-12-10
2004-01-11
2004-01-12
2004-03-07
2004-04-25
2004-05-16
2004-07-28
2004-08-11
2004-09-19
0.26
0.27
0.28
0.29
0.30
0.31
0.32
0.33
1.0
1.2
1.3
1.4
1.4-p1
1.4-p2
1.4-p3
1.4-p4
1.4-p5
1.5
1.6
1.6.1
1.6.2
1.6.3
1.4-p6
1.7
1.7.1
1.7.2
1.7.3
1.7.4
1.7.5
1.7.6
1.7.7
1.7.8
1.7.9
1.8
1.8.1
1.8.2
1.8.3
1.8.4
1.8.5
1.9
1.9.1
1.9.2
1706
1706
1964
2299
2544
2877
3058
3110
3134
6089
6415
7240
7251
7268
7312
7321
7228
8016
8465
8544
8575
8600
7332
9189
9229
9334
9389
9429
9429
9442
9443
9444
9444
7171
7217
7217
7214
7214
7240
7508
7512
7512
385
422
426
426
439
439
439
426
475
475
475
475
475
455
471
475
475
475
475
475
475
475
475
475
585
663
663
686
686
686
715
715
715
122
600
1136
1136
1136
1153
1790
1790
1790
1790
1790
1790
1790
1790
1790
1790
7730
7726
7726
7735
7736
7736
7794
7794
7794
438 (36)
438 (36)
934 (33)
936 (33)
919 (32)
919 (32)
921 (31)
926 (31)
973 (32)
1294 (36)
1470 (39)
1591 (40)
1591 (40)
1591 (40)
1591 (40)
1591 (40)
1596 (40)
2654 (39)
2732 (39)
2741 (39)
2800 (39)
2809 (39)
1596 (40)
2965 (39)
2977 (39)
2988 (39)
3023 (39)
3031 (39)
3033 (39)
3033 (39)
3041 (39)
3041 (39)
3048 (39)
3236 (39)
3287 (39)
3288 (39)
3303 (39)
3310 (39)
3299 (39)
3352 (40)
3354 (40)
3354 (40)
85 (1)
85 (1)
85 (1)
105 (1)
105 (1)
592 (23)
741 (26)
734 (23)
734 (23)
734 (23)
734 (23)
734 (23)
734 (23)
1166 (32)
1603 (31)
1603 (31)
1609 (31)
1609 (31)
735 (24)
1606 (33)
1606 (33)
1606 (33)
1651 (34)
1644 (34)
1645 (34)
1660 (34)
1660 (34)
1660 (34)
1660 (34)
1666 (36)
1686 (36)
1686 (36)
1695 (36)
1701 (36)
1701 (36)
1812 (37)
1812 (37)
1812 (37)
16
16
16
17
20
29
30
30
30
37
39
51
51
49
49
49
51
63
66
66
67
67
49
73
73
77
84
85
85
85
90
90
90
104
104
104
111
112
112
115
115
132
9
17
26
35
38
126
156
197
197
197
197
198
198
327
365
372
386
391
197
430
437
445
448
458
459
461
467
468
468
521
525
526
530
531
533
551
552
554
Appendix A: Copying This Manual
123
Appendix A Copying This Manual
A.1 GNU Free Documentation License
Version 1.2, November 2002
c 2000,2001,2002 Free Software Foundation, Inc.
Copyright 51 Franklin St, Fifth Floor, Boston, MA 02110-1301, USA
Everyone is permitted to copy and distribute verbatim copies
of this license document, but changing it is not allowed.
0. PREAMBLE
The purpose of this License is to make a manual, textbook, or other functional and
useful document free in the sense of freedom: to assure everyone the effective freedom
to copy and redistribute it, with or without modifying it, either commercially or noncommercially. Secondarily, this License preserves for the author and publisher a way
to get credit for their work, while not being considered responsible for modifications
made by others.
This License is a kind of “copyleft”, which means that derivative works of the document
must themselves be free in the same sense. It complements the GNU General Public
License, which is a copyleft license designed for free software.
We have designed this License in order to use it for manuals for free software, because
free software needs free documentation: a free program should come with manuals
providing the same freedoms that the software does. But this License is not limited to
software manuals; it can be used for any textual work, regardless of subject matter or
whether it is published as a printed book. We recommend this License principally for
works whose purpose is instruction or reference.
1. APPLICABILITY AND DEFINITIONS
This License applies to any manual or other work, in any medium, that contains a
notice placed by the copyright holder saying it can be distributed under the terms
of this License. Such a notice grants a world-wide, royalty-free license, unlimited in
duration, to use that work under the conditions stated herein. The “Document”,
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A “Modified Version” of the Document means any work containing the Document or
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another language.
A “Secondary Section” is a named appendix or a front-matter section of the Document
that deals exclusively with the relationship of the publishers or authors of the Document
to the Document’s overall subject (or to related matters) and contains nothing that
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textbook of mathematics, a Secondary Section may not explain any mathematics.) The
relationship could be a matter of historical connection with the subject or with related
matters, or of legal, commercial, philosophical, ethical or political position regarding
them.
Appendix A: Copying This Manual
124
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The Document may include Warranty Disclaimers next to the notice which states that
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be included by reference in this License, but only as regards disclaiming warranties:
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2. VERBATIM COPYING
Appendix A: Copying This Manual
125
You may copy and distribute the Document in any medium, either commercially or
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notice saying this License applies to the Document are reproduced in all copies, and
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If you publish or distribute Opaque copies of the Document numbering more than 100,
you must either include a machine-readable Transparent copy along with each Opaque
copy, or state in or with each Opaque copy a computer-network location from which
the general network-using public has access to download using public-standard network
protocols a complete Transparent copy of the Document, free of added material. If
you use the latter option, you must take reasonably prudent steps, when you begin
distribution of Opaque copies in quantity, to ensure that this Transparent copy will
remain thus accessible at the stated location until at least one year after the last time
you distribute an Opaque copy (directly or through your agents or retailers) of that
edition to the public.
It is requested, but not required, that you contact the authors of the Document well
before redistributing any large number of copies, to give them a chance to provide you
with an updated version of the Document.
4. MODIFICATIONS
You may copy and distribute a Modified Version of the Document under the conditions
of sections 2 and 3 above, provided that you release the Modified Version under precisely
this License, with the Modified Version filling the role of the Document, thus licensing
distribution and modification of the Modified Version to whoever possesses a copy of
it. In addition, you must do these things in the Modified Version:
A. Use in the Title Page (and on the covers, if any) a title distinct from that of the
Document, and from those of previous versions (which should, if there were any,
Appendix A: Copying This Manual
126
be listed in the History section of the Document). You may use the same title as
a previous version if the original publisher of that version gives permission.
B. List on the Title Page, as authors, one or more persons or entities responsible for
authorship of the modifications in the Modified Version, together with at least five
of the principal authors of the Document (all of its principal authors, if it has fewer
than five), unless they release you from this requirement.
C. State on the Title page the name of the publisher of the Modified Version, as the
publisher.
D. Preserve all the copyright notices of the Document.
E. Add an appropriate copyright notice for your modifications adjacent to the other
copyright notices.
F. Include, immediately after the copyright notices, a license notice giving the public
permission to use the Modified Version under the terms of this License, in the form
shown in the Addendum below.
G. Preserve in that license notice the full lists of Invariant Sections and required Cover
Texts given in the Document’s license notice.
H. Include an unaltered copy of this License.
I. Preserve the section Entitled “History”, Preserve its Title, and add to it an item
stating at least the title, year, new authors, and publisher of the Modified Version
as given on the Title Page. If there is no section Entitled “History” in the Document, create one stating the title, year, authors, and publisher of the Document
as given on its Title Page, then add an item describing the Modified Version as
stated in the previous sentence.
J. Preserve the network location, if any, given in the Document for public access to
a Transparent copy of the Document, and likewise the network locations given in
the Document for previous versions it was based on. These may be placed in the
“History” section. You may omit a network location for a work that was published
at least four years before the Document itself, or if the original publisher of the
version it refers to gives permission.
K. For any section Entitled “Acknowledgements” or “Dedications”, Preserve the Title
of the section, and preserve in the section all the substance and tone of each of the
contributor acknowledgements and/or dedications given therein.
L. Preserve all the Invariant Sections of the Document, unaltered in their text and
in their titles. Section numbers or the equivalent are not considered part of the
section titles.
M. Delete any section Entitled “Endorsements”. Such a section may not be included
in the Modified Version.
N. Do not retitle any existing section to be Entitled “Endorsements” or to conflict in
title with any Invariant Section.
O. Preserve any Warranty Disclaimers.
If the Modified Version includes new front-matter sections or appendices that qualify
as Secondary Sections and contain no material copied from the Document, you may at
your option designate some or all of these sections as invariant. To do this, add their
Appendix A: Copying This Manual
127
titles to the list of Invariant Sections in the Modified Version’s license notice. These
titles must be distinct from any other section titles.
You may add a section Entitled “Endorsements”, provided it contains nothing but
endorsements of your Modified Version by various parties—for example, statements of
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definition of a standard.
You may add a passage of up to five words as a Front-Cover Text, and a passage of up
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The author(s) and publisher(s) of the Document do not by this License give permission
to use their names for publicity for or to assert or imply endorsement of any Modified
Version.
5. COMBINING DOCUMENTS
You may combine the Document with other documents released under this License,
under the terms defined in section 4 above for modified versions, provided that you
include in the combination all of the Invariant Sections of all of the original documents,
unmodified, and list them all as Invariant Sections of your combined work in its license
notice, and that you preserve all their Warranty Disclaimers.
The combined work need only contain one copy of this License, and multiple identical
Invariant Sections may be replaced with a single copy. If there are multiple Invariant
Sections with the same name but different contents, make the title of each such section
unique by adding at the end of it, in parentheses, the name of the original author or
publisher of that section if known, or else a unique number. Make the same adjustment
to the section titles in the list of Invariant Sections in the license notice of the combined
work.
In the combination, you must combine any sections Entitled “History” in the various original documents, forming one section Entitled “History”; likewise combine any
sections Entitled “Acknowledgements”, and any sections Entitled “Dedications”. You
must delete all sections Entitled “Endorsements.”
6. COLLECTIONS OF DOCUMENTS
You may make a collection consisting of the Document and other documents released
under this License, and replace the individual copies of this License in the various
documents with a single copy that is included in the collection, provided that you
follow the rules of this License for verbatim copying of each of the documents in all
other respects.
You may extract a single document from such a collection, and distribute it individually under this License, provided you insert a copy of this License into the extracted
document, and follow this License in all other respects regarding verbatim copying of
that document.
Appendix A: Copying This Manual
128
7. AGGREGATION WITH INDEPENDENT WORKS
A compilation of the Document or its derivatives with other separate and independent
documents or works, in or on a volume of a storage or distribution medium, is called
an “aggregate” if the copyright resulting from the compilation is not used to limit the
legal rights of the compilation’s users beyond what the individual works permit. When
the Document is included in an aggregate, this License does not apply to the other
works in the aggregate which are not themselves derivative works of the Document.
If the Cover Text requirement of section 3 is applicable to these copies of the Document,
then if the Document is less than one half of the entire aggregate, the Document’s Cover
Texts may be placed on covers that bracket the Document within the aggregate, or the
electronic equivalent of covers if the Document is in electronic form. Otherwise they
must appear on printed covers that bracket the whole aggregate.
8. TRANSLATION
Translation is considered a kind of modification, so you may distribute translations
of the Document under the terms of section 4. Replacing Invariant Sections with
translations requires special permission from their copyright holders, but you may
include translations of some or all Invariant Sections in addition to the original versions
of these Invariant Sections. You may include a translation of this License, and all the
license notices in the Document, and any Warranty Disclaimers, provided that you
also include the original English version of this License and the original versions of
those notices and disclaimers. In case of a disagreement between the translation and
the original version of this License or a notice or disclaimer, the original version will
prevail.
If a section in the Document is Entitled “Acknowledgements”, “Dedications”, or “History”, the requirement (section 4) to Preserve its Title (section 1) will typically require
changing the actual title.
9. TERMINATION
You may not copy, modify, sublicense, or distribute the Document except as expressly
provided for under this License. Any other attempt to copy, modify, sublicense or
distribute the Document is void, and will automatically terminate your rights under
this License. However, parties who have received copies, or rights, from you under this
License will not have their licenses terminated so long as such parties remain in full
compliance.
10. FUTURE REVISIONS OF THIS LICENSE
The Free Software Foundation may publish new, revised versions of the GNU Free
Documentation License from time to time. Such new versions will be similar in spirit
to the present version, but may differ in detail to address new problems or concerns.
See http://www.gnu.org/copyleft/.
Each version of the License is given a distinguishing version number. If the Document
specifies that a particular numbered version of this License “or any later version”
applies to it, you have the option of following the terms and conditions either of that
specified version or of any later version that has been published (not as a draft) by
the Free Software Foundation. If the Document does not specify a version number of
this License, you may choose any version ever published (not as a draft) by the Free
Software Foundation.
Appendix A: Copying This Manual
129
A.1.1 ADDENDUM: How to use this License for your documents
To use this License in a document you have written, include a copy of the License in the
document and put the following copyright and license notices just after the title page:
Copyright (C) year your name.
Permission is granted to copy, distribute and/or modify this document
under the terms of the GNU Free Documentation License, Version 1.2
or any later version published by the Free Software Foundation;
with no Invariant Sections, no Front-Cover Texts, and no Back-Cover
Texts. A copy of the license is included in the section entitled ‘‘GNU
Free Documentation License’’.
If you have Invariant Sections, Front-Cover Texts and Back-Cover Texts, replace the
“with...Texts.” line with this:
with the Invariant Sections being list their titles, with
the Front-Cover Texts being list, and with the Back-Cover Texts
being list.
If you have Invariant Sections without Cover Texts, or some other combination of the
three, merge those two alternatives to suit the situation.
If your document contains nontrivial examples of program code, we recommend releasing
these examples in parallel under your choice of free software license, such as the GNU
General Public License, to permit their use in free software.
Appendix B: Indices
130
Appendix B Indices
B.1 Macro Index
_AM_DEPENDENCIES . . . . . . . . . . . . . . . . . . . . . . . . . . . 21
A
AC_CANONICAL_BUILD . . . . . . . . . . . . . . . . . . . . . . . . .
AC_CANONICAL_HOST . . . . . . . . . . . . . . . . . . . . . . . . . .
AC_CANONICAL_TARGET . . . . . . . . . . . . . . . . . . . . . . . .
AC_CONFIG_AUX_DIR . . . . . . . . . . . . . . . . . . . . . . 13,
AC_CONFIG_FILES . . . . . . . . . . . . . . . . . . . . . . . . . . . .
AC_CONFIG_HEADERS . . . . . . . . . . . . . . . . . . . . . . . . . .
AC_CONFIG_LIBOBJ_DIR . . . . . . . . . . . . . . . . . . . . . . .
AC_CONFIG_LINKS . . . . . . . . . . . . . . . . . . . . . . . . . . . .
AC_CONFIG_SUBDIRS . . . . . . . . . . . . . . . . . . . . . . . . . .
AC_DEFUN. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
AC_F77_LIBRARY_LDFLAGS . . . . . . . . . . . . . . . . . . . .
AC_INIT . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
AC_LIBOBJ . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14, 39,
AC_LIBSOURCE . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14,
AC_LIBSOURCES . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
AC_OUTPUT . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
AC_PREREQ . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
AC_PROG_CC_C_O . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
AC_PROG_CXX . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
AC_PROG_F77 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
AC_PROG_FC . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
AC_PROG_LEX . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15,
AC_PROG_LIBTOOL . . . . . . . . . . . . . . . . . . . . . . . . . . . .
AC_PROG_RANLIB . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
14
14
14
29
13
13
45
13
29
22
14
19
44
44
14
13
22
20
14
14
14
20
15
14
AC_PROG_YACC . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
AC_SUBST. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
AM_C_PROTOTYPES . . . . . . . . . . . . . . . . . . . . . 15, 19,
AM_CONDITIONAL . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
AM_CONFIG_HEADER . . . . . . . . . . . . . . . . . . . . . . . . . . .
AM_DEP_TRACK . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
AM_ENABLE_MULTILIB . . . . . . . . . . . . . . . . . . . . . . . . .
AM_GNU_GETTEXT . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
AM_HEADER_TIOCGWINSZ_NEEDS_SYS_IOCTL . . . . .
AM_INIT_AUTOMAKE . . . . . . . . . . . . . . . . . . . . . . . 12,
AM_MAINTAINER_MODE . . . . . . . . . . . . . . . . . . 15, 75,
AM_MAKE_INCLUDE . . . . . . . . . . . . . . . . . . . . . . . . . . . .
AM_OUTPUT_DEPENDENCY_COMMANDS . . . . . . . . . . . . .
AM_PATH_LISPDIR . . . . . . . . . . . . . . . . . . . . . . . . . . . .
AM_PATH_PYTHON . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
AM_PROG_AS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
AM_PROG_CC_C_O . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
AM_PROG_GCJ . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
AM_PROG_INSTALL_STRIP . . . . . . . . . . . . . . . . . . . . .
AM_PROG_LEX . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
AM_SANITY_CHECK . . . . . . . . . . . . . . . . . . . . . . . . . . . .
AM_SET_DEPDIR . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
AM_SYS_POSIX_TERMIOS . . . . . . . . . . . . . . . . . . . . . . .
AM_WITH_DMALLOC . . . . . . . . . . . . . . . . . . . . . . . . . . . .
AM_WITH_REGEX . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
15
15
55
81
21
21
19
15
21
19
92
21
21
20
64
20
20
20
21
20
21
21
21
20
20
M
m4_include . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15, 70
B.2 Variable Index
_DATA . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
_HEADERS. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
_LIBRARIES . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
_LISP . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
_LTLIBRARIES . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
_MANS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
_PROGRAMS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3,
_PYTHON . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
_SCRIPTS. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
_SOURCES . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31,
_TEXINFOS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 65,
58
57
34
62
35
67
30
64
57
44
66
A
AC_PROG_FC . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14
ACLOCAL_AMFLAGS . . . . . . . . . . . . . . . . . . . . . . . . . 23, 75
ALLOCA . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 39,
AM_CCASFLAGS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
AM_CFLAGS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
AM_CPPFLAGS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
AM_CXXFLAGS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
AM_ETAGSFLAGS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
AM_FCFLAGS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
AM_GCJFLAGS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
AM_INSTALLCHECK_STD_OPTIONS_EXEMPT . . . . . . .
AM_JAVACFLAGS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
AM_LDFLAGS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31,
AM_LFLAGS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
AM_MAKEFLAGS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
AM_MAKEINFOFLAGS . . . . . . . . . . . . . . . . . . . . . . . . . . .
AM_MAKEINFOHTMLFLAGS . . . . . . . . . . . . . . . . . . . . . . .
AM_RFLAGS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
AM_RUNTESTFLAGS . . . . . . . . . . . . . . . . . . . . . . . . . . . .
AM_YFLAGS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
44
49
46
46
49
80
50
54
78
63
47
47
25
67
67
50
74
47
Appendix B: Indices
ANSI2KNR. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
AUTOCONF. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
AUTOM4TE. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
AUTOMAKE_OPTIONS . . . . . . . . . . . . . . . . . 19, 55, 56,
131
19
10
16
76
B
bin_PROGRAMS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
bin_SCRIPTS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
build_triplet . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
BUILT_SOURCES . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
30
57
14
58
EXTRA_maude_SOURCES . . . . . . . . . . . . . . . . . . . . . . . . 41
EXTRA_PROGRAMS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 33
F
F77LINK . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
FC . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
FCCOMPILE . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
FCFLAGS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
FCLIBS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
FCLINK . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 50,
C
G
CC . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 46
CCAS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20, 49
CCASFLAGS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20, 49
CFLAGS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 46
check_ . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4
check_LTLIBRARIES . . . . . . . . . . . . . . . . . . . . . . . . . . 37
check_PROGRAMS . . . . . . . . . . . . . . . . . . . . . . . . . . 30, 44
check_SCRIPTS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 57
CLASSPATH_ENV . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 64
CLEANFILES . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 70
COMPILE . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 46
CONFIG_STATUS_DEPENDENCIES . . . . . . . . . . . . . . . . 75
CONFIGURE_DEPENDENCIES . . . . . . . . . . . . . . . . . . . . 75
CPPFLAGS. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 46
CXX . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 49
CXXCOMPILE . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 49
CXXFLAGS. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 49
CXXLINK . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 49, 54
GCJ . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
GCJFLAGS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20,
GCJLINK . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
GTAGS_ARGS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
GZIP_ENV. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
54
50
50
50
53
54
20
54
54
80
70
H
HEADERS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4
host_triplet . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14
I
include_HEADERS . . . . . . . . . . . . . . . . . . . . . . . . . . . . 57
INCLUDES . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8, 46
info_TEXINFOS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 65
J
D
DATA. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4,
data_DATA . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
DEFS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
DEJATOOL. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
DESTDIR . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
dist_ . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28,
dist_lisp_LISP . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
dist_noinst_LISP . . . . . . . . . . . . . . . . . . . . . . . . . . .
DIST_SUBDIRS . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26,
DISTCHECK_CONFIGURE_FLAGS . . . . . . . . . . . . . . . . .
distcleancheck_listfiles . . . . . . . . . . . . . . . 72,
DISTCLEANFILES . . . . . . . . . . . . . . . . . . . . . . . . . . 70,
distdir . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 71,
distuninstallcheck_listfiles . . . . . . . . . . . . . .
DVIPS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
58
58
46
74
69
71
62
62
71
72
95
72
85
72
67
E
EMACS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
ETAGS_ARGS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
ETAGSFLAGS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
EXPECT . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
EXTRA_DIST . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
20
80
80
74
71
JAVA . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4
JAVAC . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 63
JAVACFLAGS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 63
JAVAROOT. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 63
L
LDADD . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31
LDFLAGS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 46
LFLAGS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 47
lib_LIBRARIES . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 34
lib_LTLIBRARIES . . . . . . . . . . . . . . . . . . . . . . . . . . . . 35
libexec_PROGRAMS . . . . . . . . . . . . . . . . . . . . . . . . . . . 30
libexec_SCRIPTS . . . . . . . . . . . . . . . . . . . . . . . . . . . . 57
LIBOBJS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14, 39, 44
LIBRARIES. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4
LIBS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 46
LINK . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 47, 54
LISP . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4
lisp_LISP . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 62
lispdir . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20
localstate_DATA . . . . . . . . . . . . . . . . . . . . . . . . . . . . 58
LTALLOCA . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 39, 44
LTLIBOBJS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 39, 44
Appendix B: Indices
M
MAINTAINERCLEANFILES . . . . . . . . . . . . . . . . . . . . . . . 70
MAKE . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25
MAKEINFO. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 66
MAKEINFOFLAGS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 66
MAKEINFOHTML . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 66
man_MANS. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 67
MANS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4
maude_AR. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 41
maude_CCASFLAGS . . . . . . . . . . . . . . . . . . . . . . . . . . . . 43
maude_CFLAGS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 43
maude_CPPFLAGS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 43
maude_CXXFLAGS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 43
maude_DEPENDENCIES . . . . . . . . . . . . . . . . . . . . . 31, 42
maude_FFLAGS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 43
maude_GCJFLAGS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 43
maude_LDADD . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31, 42
maude_LDFLAGS . . . . . . . . . . . . . . . . . . . . . . . . . . . 31, 42
maude_LFLAGS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 43
maude_LIBADD . . . . . . . . . . . . . . . . . . . . . . . . . . . . 34, 42
maude_LINK . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 42
maude_OBJCFLAGS . . . . . . . . . . . . . . . . . . . . . . . . . . . . 43
maude_RFLAGS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 43
maude_SHORTNAME . . . . . . . . . . . . . . . . . . . . . . . . . . . . 43
maude_SOURCES . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 40
maude_YFLAGS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 43
MOSTLYCLEANFILES . . . . . . . . . . . . . . . . . . . . . . . . . . . 70
132
pkgpythondir . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 65
PROGRAMS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3, 4
pyexecdir . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 65
PYTHON . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4, 64
PYTHON_EXEC_PREFIX . . . . . . . . . . . . . . . . . . . . . . . . . 65
PYTHON_PLATFORM . . . . . . . . . . . . . . . . . . . . . . . . . . . . 65
PYTHON_PREFIX . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 65
PYTHON_VERSION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 64
pythondir . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 65
R
RFLAGS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
RUNTEST . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
RUNTESTDEFAULTFLAGS . . . . . . . . . . . . . . . . . . . . . . . .
RUNTESTFLAGS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
S
sbin_PROGRAMS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
sbin_SCRIPTS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
SCRIPTS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4,
sharedstate_DATA . . . . . . . . . . . . . . . . . . . . . . . . . . .
SOURCES . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31,
SUBDIRS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25,
SUFFIXES. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
sysconf_DATA . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
N
T
nobase_ . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28
nodist_ . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28, 71
noinst_ . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4
noinst_HEADERS . . . . . . . . . . . . . . . . . . . . . . . . . . 57, 58
noinst_LIBRARIES . . . . . . . . . . . . . . . . . . . . . . . . . . . 34
noinst_LISP . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 62
noinst_LTLIBRARIES . . . . . . . . . . . . . . . . . . . . . . . . . 37
noinst_PROGRAMS . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30
noinst_SCRIPTS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 57
TAGS_DEPENDENCIES . . . . . . . . . . . . . . . . . . . . . . . . . .
target_triplet . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
TESTS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
TESTS_ENVIRONMENT . . . . . . . . . . . . . . . . . . . . . . . . . .
TEXI2DVI. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
TEXI2PDF. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
TEXINFO_TEX . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
TEXINFOS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4,
top_distdir . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 71,
O
OBJCLINK. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 54
oldinclude_HEADERS . . . . . . . . . . . . . . . . . . . . . . . . . 57
P
PACKAGE . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 70
pkgdata_DATA . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 58
pkgdata_SCRIPTS . . . . . . . . . . . . . . . . . . . . . . . . . . . . 57
pkgdatadir . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3
pkginclude_HEADERS . . . . . . . . . . . . . . . . . . . . . . . . . 57
pkgincludedir . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3
pkglib_LIBRARIES . . . . . . . . . . . . . . . . . . . . . . . . . . . 34
pkglib_LTLIBRARIES . . . . . . . . . . . . . . . . . . . . . . . . . 35
pkglib_PROGRAMS . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30
pkglibdir. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3
pkgpyexecdir . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 65
50
74
74
74
30
57
57
58
44
71
80
58
80
14
74
74
67
67
67
66
85
U
U . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19
V
VERSION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 70
W
WARNINGS. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12
WITH_DMALLOC . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20
WITH_REGEX . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20
X
XFAIL_TESTS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 74
Appendix B: Indices
133
Y
YFLAGS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 47
YACC . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15
B.3 General Index
#
.
## (special Automake comment) . . . . . . . . . . . . . . . 2
‘.la’ suffix, defined . . . . . . . . . . . . . . . . . . . . . . . . . . 35
$
‘$(LIBOBJS)’ and empty libraries. . . . . . . . . . . . . . 45
+
+= . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1
--acdir . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
--add-missing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
--copy . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
--cygnus. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
‘--enable-debug’, example . . . . . . . . . . . . . . . . . . .
--enable-maintainer-mode . . . . . . . . . . . . . . . . . .
--force . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
--force-missing . . . . . . . . . . . . . . . . . . . . . . . . . . . .
--foreign . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
--gnits . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
‘--gnits’, complete description . . . . . . . . . . . . . . .
--gnu . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
‘--gnu’, complete description . . . . . . . . . . . . . . . . .
‘--gnu’, required files . . . . . . . . . . . . . . . . . . . . . . . .
--help . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11,
‘--help’ check . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
--include-deps . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
--libdir. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
--no-force . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
--output. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
--output-dir . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
--print-ac-dir . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
--verbose . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11,
--version . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11,
‘--version’ check . . . . . . . . . . . . . . . . . . . . . . . . . . . .
--warnings . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
--with-dmalloc . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
--with-regex . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
-a . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
-c . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
-f . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
‘-hook’ targets. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
-i . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
-I . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
‘-local’ targets . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
‘-module’, libtool . . . . . . . . . . . . . . . . . . . . . . . . . . . .
-o . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
-v . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
-W . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
16
10
10
11
81
15
16
11
11
11
83
11
82
82
16
78
11
10
11
17
11
17
17
17
78
11
20
20
10
10
11
85
11
16
84
38
11
11
11
_DATA primary, defined . . . . . . . . . . . . . . . . . . . . . . . 58
_DEPENDENCIES, defined . . . . . . . . . . . . . . . . . . . . . . 31
_HEADERS primary, defined . . . . . . . . . . . . . . . . . . . . 57
_JAVA primary, defined . . . . . . . . . . . . . . . . . . . . . . . 63
_LDFLAGS, defined . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31
_LDFLAGS, libtool . . . . . . . . . . . . . . . . . . . . . . . . . . . . 39
_LIBADD, libtool . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 39
_LIBRARIES primary, defined . . . . . . . . . . . . . . . . . . 34
_LISP primary, defined . . . . . . . . . . . . . . . . . . . . . . . 62
_LTLIBRARIES primary, defined . . . . . . . . . . . . . . . 35
_MANS primary, defined . . . . . . . . . . . . . . . . . . . . . . . 67
_PROGRAMS primary variable. . . . . . . . . . . . . . . . . . . . 3
_PYTHON primary, defined . . . . . . . . . . . . . . . . . . . . . 64
_SCRIPTS primary, defined . . . . . . . . . . . . . . . . . . . . 57
_SOURCES and header files . . . . . . . . . . . . . . . . . . . . 31
_SOURCES primary, defined . . . . . . . . . . . . . . . . . . . . 31
_SOURCES, default . . . . . . . . . . . . . . . . . . . . . . . . . . . . 44
_SOURCES, empty . . . . . . . . . . . . . . . . . . . . . . . . . . . . 44
_TEXINFOS primary, defined . . . . . . . . . . . . . . . . . . . 65
A
AC_SUBST and SUBDIRS . . . . . . . . . . . . . . . . . . . . . . . 26
‘acinclude.m4’, defined . . . . . . . . . . . . . . . . . . . . . . . 6
aclocal program, introduction. . . . . . . . . . . . . . . . . 6
aclocal search path . . . . . . . . . . . . . . . . . . . . . . . . . 17
aclocal’s scheduled death . . . . . . . . . . . . . . . . . . . . 24
aclocal, extending . . . . . . . . . . . . . . . . . . . . . . . . . . 22
aclocal, Invoking . . . . . . . . . . . . . . . . . . . . . . . . . . . 15
aclocal, Options . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16
‘aclocal.m4’, preexisting . . . . . . . . . . . . . . . . . . . . . . 6
Adding new SUFFIXES . . . . . . . . . . . . . . . . . . . . . . . . 80
all . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 84
all-local . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 84
ALLOCA, and Libtool . . . . . . . . . . . . . . . . . . . . . . . . . . 39
ALLOCA, example . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 44
ALLOCA, special handling. . . . . . . . . . . . . . . . . . . . . . 44
AM_CCASFLAGS and CCASFLAGS . . . . . . . . . . . . . . . . . 96
AM_CFLAGS and CFLAGS . . . . . . . . . . . . . . . . . . . . . . . 96
AM_CONDITIONAL and SUBDIRS . . . . . . . . . . . . . . . . . 26
AM_CPPFLAGS and CPPFLAGS . . . . . . . . . . . . . . . . . . . 96
AM_CXXFLAGS and CXXFLAGS . . . . . . . . . . . . . . . . . . . 96
AM_FCFLAGS and FCFLAGS . . . . . . . . . . . . . . . . . . . . . 96
AM_FFLAGS and FFLAGS . . . . . . . . . . . . . . . . . . . . . . . 96
AM_GCJFLAGS and GCJFLAGS . . . . . . . . . . . . . . . . . . . 96
AM_INIT_AUTOMAKE, example use . . . . . . . . . . . . . . . 6
AM_LDFLAGS and LDFLAGS . . . . . . . . . . . . . . . . . . . . . 96
Appendix B: Indices
AM_LFLAGS and LFLAGS . . . . . . . . . . . . . . . . . . . . . . . 96
AM_MAINTAINER_MODE, purpose . . . . . . . . . . . . . . . . 92
AM_OBJCFLAGS and OBJCFLAGS . . . . . . . . . . . . . . . . . 96
AM_RFLAGS and RFLAGS . . . . . . . . . . . . . . . . . . . . . . . 96
AM_YFLAGS and YFLAGS . . . . . . . . . . . . . . . . . . . . . . . 96
ansi2knr . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 55, 76
ansi2knr and LIBOBJS . . . . . . . . . . . . . . . . . . . . . . . 55
ansi2knr and LTLIBOBJS . . . . . . . . . . . . . . . . . . . . . 55
Append operator . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1
‘autogen.sh’ and autoreconf . . . . . . . . . . . . . . . . . 39
autom4te . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16
Automake constraints . . . . . . . . . . . . . . . . . . . . . . . . . 1
automake options . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10
Automake requirements . . . . . . . . . . . . . . . . . . . . 1, 12
automake, invoking . . . . . . . . . . . . . . . . . . . . . . . . . . 10
Automake, recursive operation . . . . . . . . . . . . . . . . . 2
Automatic dependency tracking . . . . . . . . . . . . . . . 55
Automatic linker selection . . . . . . . . . . . . . . . . . . . . 54
autoreconf and libtoolize . . . . . . . . . . . . . . . . . . 39
autoupdate . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21
Auxiliary programs . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
Avoiding path stripping . . . . . . . . . . . . . . . . . . . . . . 28
B
‘bootstrap.sh’ and autoreconf . . . . . . . . . . . . . . 39
Bugs, reporting . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1
BUILT_SOURCES, defined . . . . . . . . . . . . . . . . . . . . . . 58
C
C++ support . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 49
canonicalizing Automake variables . . . . . . . . . . . . . 4
CCASFLAGS and AM_CCASFLAGS . . . . . . . . . . . . . . . . . 96
CFLAGS and AM_CFLAGS . . . . . . . . . . . . . . . . . . . . . . . 96
cfortran . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 52
check . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 73, 84
check-local . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 84
check-news . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 76
‘check_’ primary prefix, definition . . . . . . . . . . . . . . 4
check_PROGRAMS example . . . . . . . . . . . . . . . . . . . . . 44
clean . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 84
clean-local . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 70, 84
Comment, special to Automake . . . . . . . . . . . . . . . . 2
Compile Flag Variables . . . . . . . . . . . . . . . . . . . . . . . 96
Complete example . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6
Conditional example, ‘--enable-debug’. . . . . . . . 81
conditional libtool libraries . . . . . . . . . . . . . . . . . . . 36
Conditional programs . . . . . . . . . . . . . . . . . . . . . . . . 33
Conditional subdirectories . . . . . . . . . . . . . . . . . . . . 25
Conditional SUBDIRS . . . . . . . . . . . . . . . . . . . . . . . . . 25
Conditionals. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 81
‘config.guess’ . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10
‘configure.ac’, from GNU Hello. . . . . . . . . . . . . . . 7
‘configure.ac’, scanning . . . . . . . . . . . . . . . . . . . . . 12
conflicting definitions . . . . . . . . . . . . . . . . . . . . . . . . 84
Constraints of Automake . . . . . . . . . . . . . . . . . . . . . . 1
convenience libraries, libtool . . . . . . . . . . . . . . . . . . 37
134
copying semantics. . . . . . . . . . . . . . . . . . . . . . . . . . . . 84
cpio example . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3
CPPFLAGS and AM_CPPFLAGS . . . . . . . . . . . . . . . . . . . 96
CVS and generated files . . . . . . . . . . . . . . . . . . . . . . 90
CVS and third-party files . . . . . . . . . . . . . . . . . . . . . 92
CVS and timestamps . . . . . . . . . . . . . . . . . . . . . . . . 90
cvs-dist . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1
cvs-dist, non-standard example . . . . . . . . . . . . . . . 1
CXXFLAGS and AM_CXXFLAGS . . . . . . . . . . . . . . . . . . . 96
cygnus . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 76
‘cygnus’ strictness . . . . . . . . . . . . . . . . . . . . . . . . . . . 83
D
DATA primary, defined . . . . . . . . . . . . . . . . . . . . . . . .
de-ANSI-fication, defined . . . . . . . . . . . . . . . . . . . . .
default _SOURCES . . . . . . . . . . . . . . . . . . . . . . . . . . . .
default source, Libtool modules example . . . . . . .
definitions, conflicts . . . . . . . . . . . . . . . . . . . . . . . . . .
dejagnu . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 74,
depcomp . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
dependencies and distributed files . . . . . . . . . . . . .
Dependency tracking . . . . . . . . . . . . . . . . . . . . . . . . .
Dependency tracking, disabling . . . . . . . . . . . . . . .
‘dirlist’ . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Disabling dependency tracking . . . . . . . . . . . . . . . .
dist . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
dist-bzip2 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 73,
dist-gzip . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
dist-hook . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 71,
dist-shar . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 73,
dist-tarZ . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 73,
dist-zip . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 73,
dist_ and nobase_ . . . . . . . . . . . . . . . . . . . . . . . . . .
DIST_SUBDIRS, explained . . . . . . . . . . . . . . . . . . . . .
distcheck . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
distcheck-hook . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
distclean . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 84,
distclean, diagnostic . . . . . . . . . . . . . . . . . . . . . . . .
distclean-local . . . . . . . . . . . . . . . . . . . . . . . . . 70,
distcleancheck . . . . . . . . . . . . . . . . . . . . . . . . . . 72,
distdir . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
dmalloc, support for . . . . . . . . . . . . . . . . . . . . . . . . .
dvi . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
DVI output using Texinfo . . . . . . . . . . . . . . . . . . . .
dvi-local . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
58
55
44
44
84
76
55
94
55
56
18
56
70
76
73
85
76
77
76
28
26
72
72
94
94
84
94
85
20
84
65
84
E
E-mail, bug reports . . . . . . . . . . . . . . . . . . . . . . . . . . . 1
EDITION Texinfo flag . . . . . . . . . . . . . . . . . . . . . . . . . 65
else . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 82
empty _SOURCES . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 44
Empty libraries . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 34
Empty libraries and ‘$(LIBOBJS)’ . . . . . . . . . . . . . 45
endif . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 82
Example conditional ‘--enable-debug’ . . . . . . . . 81
Example of recursive operation . . . . . . . . . . . . . . . . 2
Appendix B: Indices
Example of shared libraries . . . . . . . . . . . . . . . . . . . 35
Example, EXTRA_PROGRAMS . . . . . . . . . . . . . . . . . . . . . 3
Example, false and true . . . . . . . . . . . . . . . . . . . . . 8
Example, GNU Hello . . . . . . . . . . . . . . . . . . . . . . . . . . 7
Example, handling Texinfo files . . . . . . . . . . . . . . . . 8
Example, regression test . . . . . . . . . . . . . . . . . . . . . . . 8
Executable extension . . . . . . . . . . . . . . . . . . . . . . . . . 56
Exit status 77, special interpretation . . . . . . . . . . 74
Expected test failure . . . . . . . . . . . . . . . . . . . . . . . . . 74
Extending aclocal . . . . . . . . . . . . . . . . . . . . . . . . . . 22
Extending list of installation directories. . . . . . . . . 3
Extension, executable . . . . . . . . . . . . . . . . . . . . . . . . 56
Extra files distributed with Automake . . . . . . . . . 10
EXTRA_, prepending . . . . . . . . . . . . . . . . . . . . . . . . . . . 3
EXTRA_prog_SOURCES, defined . . . . . . . . . . . . . . . . . 32
EXTRA_PROGRAMS, defined . . . . . . . . . . . . . . . . . . . 3, 33
F
false Example . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8
FCFLAGS and AM_FCFLAGS . . . . . . . . . . . . . . . . . . . . . 96
FCLIBS, defined . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 53
FDL, GNU Free Documentation License . . . . . . 123
FFLAGS and AM_FFLAGS . . . . . . . . . . . . . . . . . . . . . . . 96
filename-length-max=99 . . . . . . . . . . . . . . . . . . . . 77
Files distributed with Automake . . . . . . . . . . . . . . 10
First line of Makefile.am . . . . . . . . . . . . . . . . . . . . . . . 2
Flag variables, ordering . . . . . . . . . . . . . . . . . . . . . . 96
Flag Variables, Ordering . . . . . . . . . . . . . . . . . . . . . 96
foreign . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 76
‘foreign’ strictness . . . . . . . . . . . . . . . . . . . . . . . . . . . 2
Fortran support . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 49
Fortran, mixing with C and C++ . . . . . . . . . . . . . . 52
Fortran, Preprocessing . . . . . . . . . . . . . . . . . . . . . . . 51
G
GCJFLAGS and AM_GCJFLAGS . . . . . . . . . . . . . . . . . . . 96
generated files and CVS . . . . . . . . . . . . . . . . . . . . . . 90
generated files, distributed . . . . . . . . . . . . . . . . . . . . 90
Gettext support . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 63
gnits . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 76
‘gnits’ strictness . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2
gnu . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 76
GNU Gettext support . . . . . . . . . . . . . . . . . . . . . . . . 63
GNU Hello, ‘configure.ac’. . . . . . . . . . . . . . . . . . . . 7
GNU Hello, example . . . . . . . . . . . . . . . . . . . . . . . . . . 7
GNU make extensions . . . . . . . . . . . . . . . . . . . . . . . . . 1
GNU Makefile standards . . . . . . . . . . . . . . . . . . . . . . 1
‘gnu’ strictness. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2
‘GNUmakefile’ including ‘Makefile’ . . . . . . . . . . . 87
H
Header files in _SOURCES . . . . . . . . . . . . . . . . . . . . . . 31
HEADERS primary, defined . . . . . . . . . . . . . . . . . . . . . 57
HEADERS, installation directories . . . . . . . . . . . . . . . 57
Hello example . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7
135
Hello, ‘configure.ac’ . . . . . . . . . . . . . . . . . . . . . . . . . 7
hook targets . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 85
HP-UX 10, lex problems . . . . . . . . . . . . . . . . . . . . . 20
html . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 84
HTML output using Texinfo . . . . . . . . . . . . . . . . . . 65
html-local . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 84
I
id . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 80
if . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 82
include . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 70, 81
include, distribution. . . . . . . . . . . . . . . . . . . . . . . . . 70
INCLUDES, example usage . . . . . . . . . . . . . . . . . . . . . . 8
Including ‘Makefile’ fragment . . . . . . . . . . . . . . . . 81
info . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 77, 84
info-local . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 84
install . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 68, 84
Install hook . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 69
Install, two parts of . . . . . . . . . . . . . . . . . . . . . . . . . . 68
install-data . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 68
install-data-hook . . . . . . . . . . . . . . . . . . . . . . . . . . 85
install-data-local . . . . . . . . . . . . . . . . . . . . . 69, 84
install-exec . . . . . . . . . . . . . . . . . . . . . . . . . . . . 68, 84
install-exec-hook . . . . . . . . . . . . . . . . . . . . . . . . . . 85
install-exec-local . . . . . . . . . . . . . . . . . . . . . 69, 84
install-info . . . . . . . . . . . . . . . . . . . . . . . . . . . . 66, 77
install-info target . . . . . . . . . . . . . . . . . . . . . . . . . 66
install-man . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 68, 77
install-man target . . . . . . . . . . . . . . . . . . . . . . . . . . 68
install-strip . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 69
Installation directories, extending list . . . . . . . . . . . 3
Installation support . . . . . . . . . . . . . . . . . . . . . . . . . . 68
installcheck . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 84
installcheck-local . . . . . . . . . . . . . . . . . . . . . . . . . 84
installdirs . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 69, 84
installdirs-local . . . . . . . . . . . . . . . . . . . . . . . . . . 84
Installing headers . . . . . . . . . . . . . . . . . . . . . . . . . . . . 57
Installing scripts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 57
installing versioned binaries. . . . . . . . . . . . . . . . . . . 85
Interfacing with third-party packages . . . . . . . . . . 85
Invoking aclocal . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15
Invoking automake . . . . . . . . . . . . . . . . . . . . . . . . . . . 10
J
JAVA primary, defined . . . . . . . . . . . . . . . . . . . . . . . . 63
JAVA restrictions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 63
Java support . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 54
L
LDFLAGS and AM_LDFLAGS . . . . . . . . . . . . . . . . . . . . .
lex problems with HP-UX 10 . . . . . . . . . . . . . . . . .
lex, multiple lexers . . . . . . . . . . . . . . . . . . . . . . . . . .
LFLAGS and AM_LFLAGS . . . . . . . . . . . . . . . . . . . . . . .
‘libltdl’, introduction . . . . . . . . . . . . . . . . . . . . . . .
LIBOBJS and ansi2knr . . . . . . . . . . . . . . . . . . . . . . .
96
20
47
96
35
55
Appendix B: Indices
LIBOBJS, and Libtool. . . . . . . . . . . . . . . . . . . . . . . . .
LIBOBJS, example . . . . . . . . . . . . . . . . . . . . . . . . . . . .
LIBOBJS, special handling . . . . . . . . . . . . . . . . . . . .
LIBRARIES primary, defined . . . . . . . . . . . . . . . . . . .
libtool convenience libraries. . . . . . . . . . . . . . . . . . .
libtool libraries, conditional . . . . . . . . . . . . . . . . . . .
libtool library, definition . . . . . . . . . . . . . . . . . . . . . .
libtool modules . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Libtool modules, default source example . . . . . . .
libtool, introduction . . . . . . . . . . . . . . . . . . . . . . . .
libtoolize and autoreconf . . . . . . . . . . . . . . . . . .
libtoolize, no longer run by automake . . . . . . .
Linking Fortran with C and C++ . . . . . . . . . . . . . .
LISP primary, defined . . . . . . . . . . . . . . . . . . . . . . . .
LN_S example . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
local targets . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
LTALLOCA, special handling . . . . . . . . . . . . . . . . . . .
LTLIBOBJS and ansi2knr . . . . . . . . . . . . . . . . . . . . .
LTLIBOBJS, special handling . . . . . . . . . . . . . . . . . .
LTLIBRARIES primary, defined. . . . . . . . . . . . . . . . .
‘ltmain.sh’ not found . . . . . . . . . . . . . . . . . . . . . . . .
136
39
44
44
34
37
36
35
38
44
35
39
39
52
62
85
84
39
55
39
35
39
M
m4_include, distribution . . . . . . . . . . . . . . . . . . . . . 70
Macro search path . . . . . . . . . . . . . . . . . . . . . . . . . . . 17
Macros Automake recognizes . . . . . . . . . . . . . . . . . 13
maintainer-clean-local . . . . . . . . . . . . . . . . . . . . 70
make check . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 73
‘make clean’ support . . . . . . . . . . . . . . . . . . . . . . . . . 70
‘make dist’ . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 70
‘make distcheck’ . . . . . . . . . . . . . . . . . . . . . . . . . . . . 72
‘make distclean’, diagnostic . . . . . . . . . . . . . . . . . . 94
‘make distcleancheck’ . . . . . . . . . . . . . . . . . . . . . . . 72
‘make distuninstallcheck’. . . . . . . . . . . . . . . . . . . 72
‘make install’ support . . . . . . . . . . . . . . . . . . . . . . . 68
‘make installcheck’, testing ‘--help’ and
‘--version’ . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 78
Make rules, overriding . . . . . . . . . . . . . . . . . . . . . . . . . 2
Make targets, overriding . . . . . . . . . . . . . . . . . . . . . . . 2
‘Makefile’ fragment, including . . . . . . . . . . . . . . . . 81
Makefile.am, first line . . . . . . . . . . . . . . . . . . . . . . . . . 2
MANS primary, defined . . . . . . . . . . . . . . . . . . . . . . . . 67
many outputs, rules with . . . . . . . . . . . . . . . . . . . . 100
‘mdate-sh’ . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 65
missing, purpose . . . . . . . . . . . . . . . . . . . . . . . . . . . . 92
Mixing Fortran with C and C++ . . . . . . . . . . . . . . 52
Mixing Fortran with C and/or C++. . . . . . . . . . . . 52
modules, libtool . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 38
mostlyclean . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 84
mostlyclean-local . . . . . . . . . . . . . . . . . . . . . . 70, 84
Multiple ‘configure.ac’ files . . . . . . . . . . . . . . . . . 10
Multiple lex lexers . . . . . . . . . . . . . . . . . . . . . . . . . . 47
multiple outputs, rules with . . . . . . . . . . . . . . . . . 100
Multiple yacc parsers . . . . . . . . . . . . . . . . . . . . . . . . 47
N
Nesting packages . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29
no-define . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20, 77
no-dependencies . . . . . . . . . . . . . . . . . . . . . . . . . 56, 77
no-dist . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 77
no-dist-gzip . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 77
no-exeext . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 77
no-installinfo . . . . . . . . . . . . . . . . . . . . . . . . . . 66, 77
no-installman . . . . . . . . . . . . . . . . . . . . . . . . . . . 68, 77
no-texinfo.tex . . . . . . . . . . . . . . . . . . . . . . . . . . 66, 77
nobase_ and dist_ or nodist_. . . . . . . . . . . . . . . . 28
nobase_ prefix . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28
nodist_ and nobase_ . . . . . . . . . . . . . . . . . . . . . . . . 28
‘noinst_’ primary prefix, definition. . . . . . . . . . . . . 4
noinstall-info option . . . . . . . . . . . . . . . . . . . . . . 66
‘noinstall-man’ option . . . . . . . . . . . . . . . . . . . . . . 68
Non-GNU packages . . . . . . . . . . . . . . . . . . . . . . . . . . . 2
Non-standard targets. . . . . . . . . . . . . . . . . . . . . . . . . . 1
nostdinc. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 77
O
OBJCFLAGS and AM_OBJCFLAGS . . . . . . . . . . . . . . . . .
Objects in subdirectory . . . . . . . . . . . . . . . . . . . . . .
obsolete macros . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Option, ‘--warnings=category ’ . . . . . . . . . . . . . .
Option, ‘-Wcategory ’ . . . . . . . . . . . . . . . . . . . . . . . .
Option, ‘ansi2knr’ . . . . . . . . . . . . . . . . . . . . . . . . . . .
Option, ‘check-news’ . . . . . . . . . . . . . . . . . . . . . . . .
Option, ‘cygnus’ . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Option, ‘dejagnu’ . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Option, ‘dist-bzip2’ . . . . . . . . . . . . . . . . . . . . . . . .
Option, ‘dist-shar’. . . . . . . . . . . . . . . . . . . . . . . . . .
Option, ‘dist-tarZ’. . . . . . . . . . . . . . . . . . . . . . . . . .
Option, ‘dist-zip’ . . . . . . . . . . . . . . . . . . . . . . . . . . .
Option, ‘filename-length-max=99’ . . . . . . . . . . .
Option, ‘foreign’ . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Option, ‘gnits’ . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Option, ‘gnu’ . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Option, ‘no-define’. . . . . . . . . . . . . . . . . . . . . . . . . .
Option, ‘no-dependencies’ . . . . . . . . . . . . . . . . . . .
Option, ‘no-dist’ . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Option, ‘no-dist-gzip’ . . . . . . . . . . . . . . . . . . . . . .
Option, ‘no-exeext’. . . . . . . . . . . . . . . . . . . . . . . . . .
Option, ‘no-installinfo’ . . . . . . . . . . . . . . . . . . . .
Option, ‘no-installman’ . . . . . . . . . . . . . . . . . . . . .
Option, ‘no-texinfo.tex’ . . . . . . . . . . . . . . . . . . . .
Option, noinstall-info . . . . . . . . . . . . . . . . . . . . .
Option, ‘noinstall-man’ . . . . . . . . . . . . . . . . . . . . .
Option, ‘nostdinc’ . . . . . . . . . . . . . . . . . . . . . . . . . . .
Option, ‘readme-alpha’ . . . . . . . . . . . . . . . . . . . . . .
Option, ‘tar-pax’ . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Option, ‘tar-ustar’. . . . . . . . . . . . . . . . . . . . . . . . . .
Option, ‘tar-v7’ . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Option, version . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Option, warnings . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Options, aclocal . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Options, automake . . . . . . . . . . . . . . . . . . . . . . . . . . .
96
41
21
79
79
76
76
76
76
76
76
77
76
77
76
76
76
77
77
77
77
77
77
77
77
66
68
77
77
78
78
78
79
79
16
10
Appendix B: Indices
Options, ‘std-options’. . . . . . . . . . . . . . . . . . . . . . . 78
Options, ‘subdir-objects’ . . . . . . . . . . . . . . . . . . . 78
Ordering flag variables . . . . . . . . . . . . . . . . . . . . . . . 96
Overriding make rules . . . . . . . . . . . . . . . . . . . . . . . . . 2
Overriding make targets . . . . . . . . . . . . . . . . . . . . . . . 2
Overriding make variables . . . . . . . . . . . . . . . . . . . . . 2
overriding rules . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 84
overriding semantics . . . . . . . . . . . . . . . . . . . . . . . . . 84
P
PACKAGE, directory . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3
PACKAGE, prevent definition . . . . . . . . . . . . . . . . . . . 20
Path stripping, avoiding . . . . . . . . . . . . . . . . . . . . . . 28
pax format . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 78
pdf . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 84
PDF output using Texinfo . . . . . . . . . . . . . . . . . . . . 65
pdf-local . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 84
Per-object flags, emulated . . . . . . . . . . . . . . . . . . . . 99
per-target compilation flags, defined . . . . . . . . . . . 43
pkgdatadir, defined . . . . . . . . . . . . . . . . . . . . . . . . . . . 3
pkgincludedir, defined . . . . . . . . . . . . . . . . . . . . . . . 3
pkglibdir, defined . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3
POSIX termios headers . . . . . . . . . . . . . . . . . . . . . . 21
Preprocessing Fortran . . . . . . . . . . . . . . . . . . . . . . . . 51
Primary variable, DATA . . . . . . . . . . . . . . . . . . . . . . . 58
Primary variable, defined . . . . . . . . . . . . . . . . . . . . . . 3
Primary variable, HEADERS . . . . . . . . . . . . . . . . . . . . 57
Primary variable, JAVA . . . . . . . . . . . . . . . . . . . . . . . 63
Primary variable, LIBRARIES . . . . . . . . . . . . . . . . . . 34
Primary variable, LISP . . . . . . . . . . . . . . . . . . . . . . . 62
Primary variable, LTLIBRARIES . . . . . . . . . . . . . . . 35
Primary variable, MANS . . . . . . . . . . . . . . . . . . . . . . . 67
Primary variable, PROGRAMS . . . . . . . . . . . . . . . . . . . . 3
Primary variable, PYTHON . . . . . . . . . . . . . . . . . . . . . 64
Primary variable, SCRIPTS . . . . . . . . . . . . . . . . . . . . 57
Primary variable, SOURCES . . . . . . . . . . . . . . . . . . . . 31
Primary variable, TEXINFOS . . . . . . . . . . . . . . . . . . . 65
prog_LDADD, defined. . . . . . . . . . . . . . . . . . . . . . . . . . 31
PROGRAMS primary variable . . . . . . . . . . . . . . . . . . . . . 3
Programs, auxiliary . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
PROGRAMS, bindir . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30
Programs, conditional . . . . . . . . . . . . . . . . . . . . . . . . 33
Proxy ‘Makefile’ for third-party packages . . . . . 87
ps . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 84
PS output using Texinfo. . . . . . . . . . . . . . . . . . . . . . 65
ps-local. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 84
PYTHON primary, defined . . . . . . . . . . . . . . . . . . . . . . 64
R
Ratfor programs . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 51
readme-alpha . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 77
‘README-alpha’ . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 83
rebuild rules . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 75, 90
Recognized macros by Automake. . . . . . . . . . . . . . 13
Recursive operation of Automake . . . . . . . . . . . . . . 2
recursive targets and third-party ‘Makefile’s . . . 85
137
regex package . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20
Regression test example . . . . . . . . . . . . . . . . . . . . . . . 8
Reporting bugs . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1
Requirements of Automake . . . . . . . . . . . . . . . . . . . 12
Requirements, Automake . . . . . . . . . . . . . . . . . . . . . . 1
Restrictions for JAVA . . . . . . . . . . . . . . . . . . . . . . . . . 63
RFLAGS and AM_RFLAGS . . . . . . . . . . . . . . . . . . . . . . . 96
rules with multiple outputs . . . . . . . . . . . . . . . . . . 100
rules, conflicting . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 84
rules, overriding . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 84
rx package . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20
S
Scanning ‘configure.ac’ . . . . . . . . . . . . . . . . . . . . . 12
SCRIPTS primary, defined . . . . . . . . . . . . . . . . . . . . . 57
SCRIPTS, installation directories . . . . . . . . . . . . . . . 57
Selecting the linker automatically . . . . . . . . . . . . . 54
Shared libraries, support for . . . . . . . . . . . . . . . . . . 34
‘site.exp’ . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 74
SOURCES primary, defined . . . . . . . . . . . . . . . . . . . . . 31
Special Automake comment . . . . . . . . . . . . . . . . . . . 2
std-options . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 78
Strictness, command line . . . . . . . . . . . . . . . . . . . . . 10
Strictness, defined . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2
Strictness, ‘foreign’ . . . . . . . . . . . . . . . . . . . . . . . . . . 2
Strictness, ‘gnits’ . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2
Strictness, ‘gnu’ . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2
subdir-objects . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 78
Subdirectories, building conditionally . . . . . . . . . . 25
Subdirectories, configured conditionally . . . . . . . . 27
Subdirectories, not distributed . . . . . . . . . . . . . . . . 28
Subdirectory, objects in . . . . . . . . . . . . . . . . . . . . . . 41
SUBDIRS and AC_SUBST . . . . . . . . . . . . . . . . . . . . . . . 26
SUBDIRS and AM_CONDITIONAL . . . . . . . . . . . . . . . . . 26
SUBDIRS, conditional . . . . . . . . . . . . . . . . . . . . . . . . . 25
SUBDIRS, explained . . . . . . . . . . . . . . . . . . . . . . . . . . . 25
Subpackages . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29
suffix ‘.la’, defined . . . . . . . . . . . . . . . . . . . . . . . . . . 35
suffix ‘.lo’, defined . . . . . . . . . . . . . . . . . . . . . . . . . . 35
SUFFIXES, adding . . . . . . . . . . . . . . . . . . . . . . . . . . . . 80
Support for C++ . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 49
Support for Fortran . . . . . . . . . . . . . . . . . . . . . . . . . . 49
Support for GNU Gettext . . . . . . . . . . . . . . . . . . . . 63
Support for Java . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 54
T
tags . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
‘TAGS’ support . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
tar formats . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
tar-pax . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
tar-ustar . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
tar-v7 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Target, install-info . . . . . . . . . . . . . . . . . . . . . . . .
Target, install-man . . . . . . . . . . . . . . . . . . . . . . . . .
termios POSIX headers . . . . . . . . . . . . . . . . . . . . . .
Test suites . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
79
79
78
78
78
78
66
68
21
73
Appendix B: Indices
138
Tests, expected failure . . . . . . . . . . . . . . . . . . . . . . . 74
Texinfo file handling example . . . . . . . . . . . . . . . . . . 8
Texinfo flag, EDITION . . . . . . . . . . . . . . . . . . . . . . . . 65
Texinfo flag, UPDATED . . . . . . . . . . . . . . . . . . . . . . . . 65
Texinfo flag, UPDATED-MONTH . . . . . . . . . . . . . . . . . . 65
Texinfo flag, VERSION . . . . . . . . . . . . . . . . . . . . . . . . 65
‘texinfo.tex’ . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 66
TEXINFOS primary, defined . . . . . . . . . . . . . . . . . . . . 65
third-party files and CVS . . . . . . . . . . . . . . . . . . . . . 92
Third-party packages, interfacing with . . . . . . . . . 85
timestamps and CVS . . . . . . . . . . . . . . . . . . . . . . . . 90
true Example . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8
V
U
wildcards . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 93
Windows . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 56
underquoted AC_DEFUN . . . . . . . . . . . . . . . . . . . . . . . 22
Uniform naming scheme . . . . . . . . . . . . . . . . . . . . . . . 3
uninstall . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 69, 84
uninstall-hook . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 85
uninstall-local . . . . . . . . . . . . . . . . . . . . . . . . . . . . 84
UPDATED Texinfo flag . . . . . . . . . . . . . . . . . . . . . . . . . 65
UPDATED-MONTH Texinfo flag . . . . . . . . . . . . . . . . . . . 65
user variables . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4
ustar format . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 78
v7 tar format . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 78
variables, conflicting . . . . . . . . . . . . . . . . . . . . . . . . . 84
Variables, overriding . . . . . . . . . . . . . . . . . . . . . . . . . . 2
variables, reserved for the user . . . . . . . . . . . . . . . . . 4
VERSION Texinfo flag . . . . . . . . . . . . . . . . . . . . . . . . . 65
VERSION, prevent definition . . . . . . . . . . . . . . . . . . . 20
‘version.m4’, example . . . . . . . . . . . . . . . . . . . . . . . 75
‘version.sh’, example . . . . . . . . . . . . . . . . . . . . . . . 75
versioned binaries, installing . . . . . . . . . . . . . . . . . . 85
W
Y
yacc, multiple parsers . . . . . . . . . . . . . . . . . . . . . . . . 47
YFLAGS and AM_YFLAGS . . . . . . . . . . . . . . . . . . . . . . . 96
ylwrap . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 47
Z
zardoz example . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7
i
Table of Contents
1
Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1
2
General ideas . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1
2.1
2.2
2.3
2.4
2.5
2.6
3
General Operation. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Strictness . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
The Uniform Naming Scheme . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
How derived variables are named . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Variables reserved for the user . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Programs automake might require . . . . . . . . . . . . . . . . . . . . . . . . . . . .
1
2
3
4
4
5
Some example packages . . . . . . . . . . . . . . . . . . . . 6
3.1
3.2
3.3
A simple example, start to finish . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6
A classic program . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7
Building true and false . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8
4
Creating a ‘Makefile.in’ . . . . . . . . . . . . . . . . . . . 10
5
Scanning ‘configure.ac’ . . . . . . . . . . . . . . . . . . . 12
5.1
5.2
5.3
5.4
5.5
Configuration requirements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Other things Automake recognizes . . . . . . . . . . . . . . . . . . . . . . . . . . .
Auto-generating aclocal.m4 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
aclocal options . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Macro search path. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
5.5.1 Modifying the macro search path: --acdir . . . . . . . . . . . . . .
5.5.2 Modifying the macro search path: -I dir . . . . . . . . . . . . . . .
5.5.3 Modifying the macro search path: ‘dirlist’ . . . . . . . . . . . . .
5.6 Autoconf macros supplied with Automake . . . . . . . . . . . . . . . . . . . .
5.6.1 Public macros . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
5.6.2 Obsolete macros . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
5.6.3 Private macros . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
5.7 Writing your own aclocal macros . . . . . . . . . . . . . . . . . . . . . . . . . . . .
5.8 Handling Local Macros . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
5.9 The Future of aclocal . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
6
12
13
15
16
17
17
17
18
19
19
21
21
22
23
24
Directories . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24
6.1
6.2
Recursing subdirectories . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Conditional Subdirectories . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
6.2.1 SUBDIRS vs. DIST_SUBDIRS . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
6.2.2 Conditional subdirectories with AM_CONDITIONAL . . . . . . . . .
6.2.3 Conditional Subdirectories with AC_SUBST . . . . . . . . . . . . . . .
6.2.4 Non-configured Subdirectories . . . . . . . . . . . . . . . . . . . . . . . . . .
6.3 An Alternative Approach to Subdirectories . . . . . . . . . . . . . . . . . . .
6.4 Nesting Packages . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
25
25
26
26
26
27
28
29
ii
7
Building Programs and Libraries . . . . . . . . . . 30
7.1
Building a program . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
7.1.1 Defining program sources . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
7.1.2 Linking the program . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
7.1.3 Conditional compilation of sources . . . . . . . . . . . . . . . . . . . . . .
7.1.3.1 Conditional compilation using _LDADD substitutions . .
7.1.3.2 Conditional compilation using Automake conditionals
.....................................................
7.1.4 Conditional compilation of programs . . . . . . . . . . . . . . . . . . . .
7.1.4.1 Conditional programs using configure substitutions
.....................................................
7.1.4.2 Conditional programs using Automake conditionals . .
7.2 Building a library . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
7.3 Building a Shared Library . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
7.3.1 The Libtool Concept . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
7.3.2 Building Libtool Libraries . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
7.3.3 Building Libtool Libraries Conditionally . . . . . . . . . . . . . . . . .
7.3.4 Libtool Libraries with Conditional Sources . . . . . . . . . . . . . . .
7.3.5 Libtool Convenience Libraries . . . . . . . . . . . . . . . . . . . . . . . . . .
7.3.6 Libtool Modules . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
7.3.7 LIBADD and LDFLAGS . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
7.3.8 LTLIBOBJS and LTALLOCA . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
7.3.9 Common Issues Related to Libtool’s Use. . . . . . . . . . . . . . . . .
7.3.9.1 ‘required file ‘./ltmain.sh’ not found’ . . . . . . . . .
7.3.9.2 Objects ‘created with both libtool and without’ . .
7.4 Program and Library Variables . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
7.5 Default _SOURCES . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
7.6 Special handling for LIBOBJS and ALLOCA . . . . . . . . . . . . . . . . . . . .
7.7 Variables used when building a program . . . . . . . . . . . . . . . . . . . . .
7.8 Yacc and Lex support . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
7.9 C++ Support . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
7.10 Assembly Support . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
7.11 Fortran Support. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
7.11.1 Overview . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
7.11.2 Compiling Fortran Files . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
7.11.3 Preprocessing Fortran . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
7.11.4 Mixing Fortran With C and C++ . . . . . . . . . . . . . . . . . . . . . .
7.11.4.1 How the Linker is Chosen . . . . . . . . . . . . . . . . . . . . . . . . .
7.12 Java Support . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
7.13 Support for Other Languages . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
7.14 Automatic de-ANSI-fication . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
7.15 Automatic dependency tracking . . . . . . . . . . . . . . . . . . . . . . . . . . . .
7.16 Support for executable extensions . . . . . . . . . . . . . . . . . . . . . . . . . .
30
30
31
32
32
32
33
33
33
34
34
35
35
36
37
37
38
39
39
39
39
40
40
43
44
46
47
49
49
49
49
51
51
52
54
54
54
55
55
56
iii
8
Other Derived Objects . . . . . . . . . . . . . . . . . . . . 57
8.1
8.2
8.3
8.4
9
Executable Scripts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Header files . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Architecture-independent data files . . . . . . . . . . . . . . . . . . . . . . . . . .
Built sources . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
8.4.1 Built sources example . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
First try . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Using BUILT_SOURCES . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Recording dependencies manually . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Build ‘bindir.h’ from ‘configure’ . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Build ‘bindir.c’, not ‘bindir.h’. . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Which is best? . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
57
57
58
58
59
59
60
60
61
61
62
Other GNU Tools . . . . . . . . . . . . . . . . . . . . . . . . 62
9.1
9.2
9.3
9.4
9.5
10
Emacs Lisp . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Gettext . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Libtool . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Java. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Python . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Building documentation . . . . . . . . . . . . . . . . . . 65
10.1
10.2
11
62
63
63
63
64
Texinfo . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 65
Man pages . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 67
What Gets Installed . . . . . . . . . . . . . . . . . . . . . 68
11.1
11.2
11.3
11.4
11.5
Basics of installation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
The two parts of install . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Extending installation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Staged installs . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Rules for the user . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
68
68
69
69
69
12
What Gets Cleaned . . . . . . . . . . . . . . . . . . . . . . 70
13
What Goes in a Distribution . . . . . . . . . . . . . 70
13.1
13.2
13.3
13.4
13.5
14
Basics of distribution . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Fine-grained distribution control . . . . . . . . . . . . . . . . . . . . . . . . . . .
The dist hook . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Checking the distribution . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
The types of distributions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
70
71
71
72
73
Support for test suites . . . . . . . . . . . . . . . . . . . 73
14.1
14.2
14.3
Simple Tests . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 74
DejaGnu Tests . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 74
Install Tests . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 75
iv
15
Rebuilding Makefiles . . . . . . . . . . . . . . . . . . . . . 75
16
Changing Automake’s Behavior. . . . . . . . . . . 76
17
Miscellaneous Rules . . . . . . . . . . . . . . . . . . . . . 79
17.1
17.2
17.3
Interfacing to etags . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 79
Handling new file extensions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 80
Support for Multilibs . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 81
18
Include . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 81
19
Conditionals. . . . . . . . . . . . . . . . . . . . . . . . . . . . . 81
20
The effect of ‘--gnu’ and ‘--gnits’ . . . . . . . . . 82
21
The effect of ‘--cygnus’ . . . . . . . . . . . . . . . . . . . 83
22
When Automake Isn’t Enough. . . . . . . . . . . . 84
22.1
22.2
Extending Automake Rules . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 84
Third-Party ‘Makefile’s . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 85
23
Distributing ‘Makefile.in’s . . . . . . . . . . . . . . . 88
24
Automake API versioning . . . . . . . . . . . . . . . . 88
25
Upgrading a Package to a Newer Automake
Version . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 89
26
Frequently Asked Questions about Automake
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 90
26.1 CVS and generated files . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
26.1.1 Background: distributed generated files . . . . . . . . . . . . . . . . .
26.1.2 Background: CVS and timestamps . . . . . . . . . . . . . . . . . . . . .
26.1.3 Living with CVS in Autoconfiscated projects . . . . . . . . . . .
26.1.4 Third-party files . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
26.2 missing and AM_MAINTAINER_MODE . . . . . . . . . . . . . . . . . . . . . . . . .
26.2.1 missing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
26.2.2 AM_MAINTAINER_MODE . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
26.3 Why doesn’t Automake support wildcards?. . . . . . . . . . . . . . . . . .
26.4 Files left in build directory after distclean . . . . . . . . . . . . . . . . . . .
26.5 Flag Variables Ordering . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
26.5.1 Compile Flag Variables. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
26.5.2 Other Variables. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
90
90
90
90
92
92
92
92
93
94
96
96
98
v
26.6
26.7
26.8
26.9
27
Why are object files sometimes renamed? . . . . . . . . . . . . . . . . . . . 98
Per-Object Flags Emulation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 99
Handling Tools that Produce Many Outputs . . . . . . . . . . . . . . . 100
Installing to Hard-Coded Locations . . . . . . . . . . . . . . . . . . . . . . . . 104
History of Automake . . . . . . . . . . . . . . . . . . . 105
27.1 Timeline . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
27.2 Dependency Tracking in Automake . . . . . . . . . . . . . . . . . . . . . . . .
27.2.1 First Take . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Bugs . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Historical Note . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
27.2.2 Dependencies As Side Effects . . . . . . . . . . . . . . . . . . . . . . . . .
Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Bugs . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
27.2.3 Dependencies for the User . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Bugs . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
27.2.4 Techniques for Computing Dependencies . . . . . . . . . . . . . .
27.2.5 Recommendations for Tool Writers . . . . . . . . . . . . . . . . . . . .
27.2.6 Future Directions for Automake’s Dependency Tracking
.......................................................
27.3 Release Statistics. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Appendix A
106
117
117
117
117
118
118
118
118
119
119
119
120
121
121
121
Copying This Manual . . . . . . . . . 123
A.1 GNU Free Documentation License . . . . . . . . . . . . . . . . . . . . . . . . . 123
A.1.1 ADDENDUM: How to use this License for your documents
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 129
Appendix B
B.1
B.2
B.3
Indices . . . . . . . . . . . . . . . . . . . . . . . 130
Macro Index. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 130
Variable Index . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 130
General Index . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 133
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