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From: JOSH%YKTVMH.BITNET@wiscvm.ARPA (Josh Knight)
Newsgroups: net.lang.c
Subject: Re: Fast code and no morals ( Really exit() semantics )
Message-ID: <1094@brl-smoke.ARPA>
Date: Wed, 19-Feb-86 03:11:14 EST
Article-I.D.: brl-smok.1094
Posted: Wed Feb 19 03:11:14 1986
Date-Received: Fri, 21-Feb-86 07:07:37 EST
Sender: news@brl-smoke.ARPA
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 > Date: 17 Feb 86 14:46:00 PST
 >
 > > Date:     Sat, 15 Feb 86 21:43:34 EST
 > >
 > > If VMS does not support exit(0) as successful termination,
 > > then VMS is WRONG and needs to fix their exit() routine.
 > >           Doug Gwyn (VLD/VMB) <gwyn@BRL.ARPA>
 >
 > I know this is naive, but then this flock is full of naive users...
 > Doug, where exactly do Kernighan & Ritchie specify the semantics of
 > the exit() procedure ?
 >
 > The common semantics seem to me to be "return to the surrounding
 > operating system level, using the argument value as the return code".
 > Unfortunately for portability, UN*X and VMS have different ideas about
 > the semantics of program return codes, but you can't say VMS is WRONG
 > just because it's DIFFERENT unless you can quote chapter and verse.
 >
 > Does the ANSI draft specify semantics for system calls ?
 >
 >             / Lars Poulsen
 >               Advanced Computer Communications
 >              <Lars @ ACC.ARPA>
 >

Chapter and verse:


From ANSI C Standard Draft Version dated 11 August 1985,
Section D.10.4.2, "The exit function" (third paragraph):

     Finally, control is returned to the host environment.  If the
     value of *status* is zero, the status returned is *successful
     termination*; otherwise an implementation-defined form of the
     status *unsuccessful termination* is returned.

From K&R, Chapter 7, Section 7, "Error Handling - Stderr and Exit"
p. 154, next to the last paragraph:

     The program also uses the standard library function *exit*, which
     terminates program execution when it is called.  The argument of
     *exit* is available to whatever process called this one, so the
     success or failure of the program can be tested by another program
     that uses this one as a sub-process.  By convention, a return value
     of 0 signals that all is well, and various non-zero values signal
     abnormal situations.



Of course, any opinions, expressed or implied are mine and not my
employers...

			Josh Knight
			IBM T.J. Watson Research Center
josh@yktvmh.BITNET,  josh.yktvmh@ibm-sj.arpa