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The âmt option does not require the Multiprocessor Fortran 90 multiprocessor
enhancement package, but to compile and run it does require Solaris 2.2 or
later. The equivalent of -mt is included automatically with -autopar,
-explicitpar, or -parallel.
On a single-processor system the generated code can run slower with the âmt
option, but not usually by a significant amount.
The Fortran 90 library libf90 is multithread safe. The FORTRAN 77 library
that is linked in if you use -mt, libF77_mt, is also multithread safe.
Restrictions for -mt
-Mdir
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With -mt, if a function does I/O, do not name that function in an I/O list.
Such I/O is called recursive I/O, and it causes the program to hang
(deadlock). Recursive I/O is unreliable anyway, but is more apt to hang
with -mt.
â¢
In general, do not combine your own multi-threaded coding with
-autopar, -explicitpar, or -parallel. Either do it all yourself or let
the compiler do it. You may get conflicts and unexpected results if you and
the compiler are both trying to manage threads with the same primitives.
Modulesâlook for Fortran 90 modules in the dir directory also.
No space is allowed between -M and dir.
By default, such files are sought in the current working directory. The -Mdir
option allows you to keep them in some other location in addition.
BackgroundâIf a file containing a Fortran 90 module is compiled, f90
generates a module file (.M file) in addition to the .o file.
ânative
Native floating pointâuse what is best for this machine.
Direct the compiler to decide which floating-point options are available on the
machine the compiler is running on, and generate code for the best one. If you
compile and link in separate steps, and you compile with the -native option,
then be sure to link with -native.
Using the Compiler
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