Path: utzoo!utgpu!jarvis.csri.toronto.edu!rutgers!ucsd!chem.ucsd.edu!tps
From: tps@chem.ucsd.edu (Tom Stockfisch)
Newsgroups: comp.lang.c
Subject: Re: comma operator
Message-ID: <512@chem.ucsd.EDU>
Date: 6 Aug 89 06:34:32 GMT
References: <10099@mpx2.mpx.com> <93@microsoft.UUCP> <10100@mpx2.mpx.com> <44c53d5b.f9df@gtephx.UUCP> <1351@cbnewsl.ATT.COM>
Reply-To: tps@chem.ucsd.edu (Tom Stockfisch)
Organization: Chemistry Dept, UC San Diego
Lines: 14

In article <1351@cbnewsl.ATT.COM> mpl@cbnewsl.ATT.COM (michael.p.lindner) writes:
>> > >		fprintf(stderr, "Can't open %s\n", file), exit(2);

>Sigh.  RTFM!  The comma operator guarantees left to right evaluation,
>and fprintf(...) and exit(...) ARE valid expressions in C.

This is valid dpANS code, but it is not currently portable.

Many C compilers do not allow void operands of comma operators.
Many libraries also declare exit() to return void.
Systems that do both will not accept the above statement.
-- 

|| Tom Stockfisch, UCSD Chemistry	tps@chem.ucsd.edu