Article 4776 of vmsnet.internals:
Ian.Miller@softel.co.uk writes:

>dpm@access2.digex.net (David P. Murphy)  referred to a system service
>SYS$SIGPRC - Cross-Process Signal Service
>
>In what version of VMS is this to be found ?

since at least V5.3, although somewhere between then and V7.0
they enhanced it to target processes outside the job tree;
i'm not sure when.  let me paste my comments from an earlier thread:

the undocumented, unsupported system service SYS$SIGPRC() is similar
to the documented, supported system service SYS$FORCEX() in that both
invade the context of another process and place a VMS condition value
(really, any four-byte integer at all, since no check is performed)
into that process.  the difference is that $FORCEX() forces that
process to call SYS$EXIT() using the passed condition value, while
$SIGPRC() forces that process to call LIB$SIGNAL() using the passed
condition value --- a much less severe result.  of course, the target
process had better have an appropriate condition handler already
established, and be able to properly interpret the passed value
instead of just mindlessly resignalling it.  one method is to reserve
an entire facility for "tickle" purposes, which leaves the low sixteen
bits available as a raw short for when you want to pass an actual
number instead of a VMS condition value.

ok
dpm
-- 
David P. Murphy             mailto:murphy@connor.datametrics.com     (work)
systems programmer          mailto:dpm@access.digex.net          (personal)
                            http://www.access.digex.net/~dpm
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