On Tue, 12 Nov 2024 08:18:00 -0600, Lionel B Dyck wrote:
> ...
> x = syscalls('OFF') /* Turn off syscalls environment */
>
An expert has counseled against this:
Date: Mon, 2 Jun 2003 20:08:28 -0400
From: William Schoen <[email protected]>
Subject: Re: SYSCALLS() Query?
I do not recommend using sycalls 'OFF'. It may clean up more than you want
yet not everything from syscalls 'ON'. It makes two calls. It calls
subcom() to delete the SYSCALL subcommand from the environment and it calls
mvsprocclp() which will undub the thread and possibly the process if this
is the last dubbed thread.
syscalls 'ON' does several things:
it makes a "trivial" syscall (sysconf) to make sure it is dubbed or dub if
not
sigprocmask() to block all signals
subcom to query the environment for the syscall subcommand. If not there
it calls subcom again to add it.
uses irxexcom to add the variables for the syscall environment
fetches bpxwrexx (the subcom routine) to avoid having TSO repeatable
refetch it
The comment about ending the program applies to running in a UNIX
environment (e.g., spawn, exec). Undubbing in that environment in a single
threaded process will terminate that process.
Bill Schoen
--
gil
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