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Suspending a Process (PH Capability Required)
If your program has PH capability, it can call the SUSPEND intrinsic to
suspend itself. In addition, the CREATEPROCESS and ACTIVATE intrinsics
also enable your program to suspend itself (explained below).
When a process suspends itself, it moves from an executing state to a
suspended state (see Figure 1-2). The process remains suspended until:
* Another process calls the ACTIVATE intrinsic to reactivate it.
* Another process (or MPE XL) deletes it from the system.
When your program suspends itself, it must specify which processes have
permission to reactivate it. You use the susp parameter to specify one
of the following three conditions:
* Only the parent process has permission to reactivate the suspended
process.
* Any child process has permission to reactivate the suspended process.
* The parent process or any child process has permission to reactivate
the suspended process.
Your program can optionally unlock a local Resource Identification Number
(RIN) with the rin parameter of SUSPEND if it has the local RIN currently
locked. Refer to the discussion of managing shared resources with RINs
in Resource Management Programmer's Guide (32650-90024).
This is an example of a SUSPEND intrinsic call:
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SUSP := 3;
RIN := 3;
SUSPEND (SUSP,RIN);
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The parameters specified in the example above are described below.
SUSP Passes activation information. The value 3 specifies
that the parent process and all child processes have
permission to reactivate the process.
RIN Passes a local RIN (3) that is unlocked when the process
is suspended.
In addition, your program can suspend itself using:
* The susp parameter of the ACTIVATE intrinsic
* Item number 10 of the CREATEPROCESS intrinsic
When a non-zero value is specified for either parameter, your program is
suspended when the specified process is activated. The value also
indicates what processes have permission to reactivate your program after
it had been suspended (in the same manner as the susp parameter of
SUSPEND).