Path: utzoo!utgpu!jarvis.csri.toronto.edu!mailrus!csd4.milw.wisc.edu!lll-winken!claris!kevin
From: kevin@claris.com (Kevin Watts)
Newsgroups: comp.lang.c
Subject: Re: comma operator
Message-ID: <10453@claris.com>
Date: 4 Aug 89 11:05:05 GMT
References: <3287@ohstpy.mps.ohio-state.edu>
Organization: Claris Corporation, Santa Clara CA
Lines: 31

From article <3287@ohstpy.mps.ohio-state.edu>, by SMITHJ@ohstpy.mps.ohio-state.edu:
> In article <1351@cbnewsl.ATT.COM>, mpl@cbnewsl.ATT.COM (michael.p.lindner) writes:
>> ***FLAME ON!***
>> Sigh.  RTFM!  The comma operator guarantees left to right evaluation,
>> and fprintf(...) and exit(...) ARE valid expressions in C.
>> sputter sputter - flame off.
> 
> Maybe I'm mistaken, but I'm sure that all the documentation I've read warns
> that the *comma* operator ----does not----- guarantee evaluation in any order.
> Specifically, the Microsoft 5.0 manual mentions this.
> 
Hmm, I'll have to check my copy when I get home.  If you're right, it's broken.

I quote from "Standard C", p.88, by P.J. Plauger & Jim Brodie (the secretary
and chairman of X3J11):
	You write X,Y to first evaluate X as a side-effects context
	expression and then to evaluate Y.  There is a sequence point
	between the evaluation of the two operands.

I hope that settles the matter for everyone.  The order IS guaranteed!

This book appears to be an excellent reference for the ANSII C language
definition.  I just got it yesterday.  $7.95 from Microsoft Press.

And now I know the name of the ISO C committee: JTC1 SC22 WG14
Makes X3J11 seem easy to remember, doesn't it?

-- 
 Kevin Watts        ! Any opinions expressed here are my own, and are not
 Claris Corporation ! neccessarily shared by anyone else.  Unless they are
 kevin@claris.com   ! patently absurd, in which case they're not mine either.