To load a *USRSPC object, use the following LOAD commands:
EXEC CICS LOAD PROGRAM(USERTBL)
If the contents of a *USRSPC are changed by a CICS program, the *USRSPC will be changed for all users accessing the *USRSPC and the changes are permanent across all user shells and control region starts. (This is not true for other CICS platforms.)
You can avoid this in the following ways: v Put the *USRSPC in a library that is not accessed by CICS or give it a name that is not used by CICS. Use the CRTDUPOBJ command using the name in the PPT either before the control region is started or before each user shell is started. v
Use the OS/400 security facilities to make the *USRSPC object read only. See the
iSeries Security Reference
for details.
Application program logical levels
Application programs running under CICS are executed at various logical levels.
The first program to receive control within a task is at the highest logical level.
When an application program is linked to another, expecting an eventual return of control, the linked-to program is considered to reside at the next lower logical level. When control is simply transferred from one application program to another, without expecting return of control, the two programs are considered to reside at the same logical level.
Link to another program expecting return
The EXEC CICS LINK command is used to pass control from an application program at one logical level to an application program at the next lower logical level. If the linked-to program is not already in main storage, it is loaded. When the EXEC CICS RETURN command is processed in the linked-to program, control is returned to the program that initiated the link, at the next sequential process instruction.
The linked-to program operates independently of the program that issues the
EXEC CICS LINK command with regard to handling exception conditions, attention identifiers, and abends. For example, the effects of EXEC CICS HANDLE commands in the linking program are not inherited by the linked-to program, but the original EXEC CICS HANDLE commands are restored on return to the linking program. You can use the EXEC CICS HANDLE ABEND command to deal with
abnormal terminations in other link levels. See “HANDLE ABEND” on page 369
for information about this command. Figure 39 shows the concept of logical levels.
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CICS for iSeries Application Programming Guide V5
