Path: utzoo!utgpu!attcan!uunet!lll-winken!lll-tis!helios.ee.lbl.gov!pasteur!ames!elroy!gryphon!vector!rpp386!jfh
From: jfh@rpp386.UUCP (The Beach Bum)
Newsgroups: comp.unix.xenix
Subject: Re: Test SCO Xenix IPC reliability
Summary: message queue version coming out soon ...
Message-ID: <5867@rpp386.UUCP>
Date: 26 Aug 88 15:30:19 GMT
References: <22012@neabbs.UUCP> <5786@rpp386.UUCP> <128@jetson.UPMA.MD.US>
Reply-To: jfh@rpp386.UUCP (The Beach Bum)
Organization: HASA, "S" Division
Lines: 22

In article <128@jetson.UPMA.MD.US> john@jetson.UPMA.MD.US (John Owens) writes:
>I think that parent() executes
>	kill (loc[2], SIGUSR1);
>before the child process executes
>	loc[2] = getpid();
>and the child process never receives a signal.

the original version busy waited and didn't use signals.  the version i
posted used signals to increase the number of interations per second,
but wasn't tested very well ...

john has found Yet Another Bug(TM) in the code, which is still further
proof as to how difficult concurrent programming can get.  without some
form of p/v operations, that program is very difficult to write.

the new version uses message queues and screams like a banshee.  that
should be final proof as to how bullet proof the message queues are
under xenix.
-- 
John F. Haugh II (jfh@rpp386.UUCP)                           HASA, "S" Division

    "If the code and the comments disagree, then both are probably wrong."
                -- Norm Schryer