[mod.computers.vax] subprocess info

GKN@SDSC.BITNET.UUCP (07/15/86)

        From:    TOLLIVER%ORN.MFENET@LLL-MFE.ARPA
        Date:    Tue, 8 Jul 86 12:47 EDT

        Subprocesses that are spawned with, for example, an image to run in the
        (optional) command-string parameter of the DCL SPAWN command will run
        until that image is completed and then essentially "logout" or
        terminate.

        But subprocesses that are spawned with no command-string parameter wait
        until the user issues the LOGOUT command before terminating.

        Is there any way for a running image to tell the difference?

No (or at least not easily).

Briefly, what happens when DCL spawns a subprocess is that it creates a
mailbox, then does a $CREPRC to make the subprocess, and then feeds it all of
your DCL symbols and per-process logical names through that mailbox.  It also
feeds the input, output, and error PPF names, and the command line to execute,
if any.

DCL in the context of the subprocess is then armed with all of the information
it needs to do what you asked it to.  Sadly, it does not make this information
available to user-level code.

gkn

---------------------------------------
Arpa:   GKN%SDSC.BITNET@WISCVM.WISC.EDU
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