Path: utzoo!attcan!utgpu!jarvis.csri.toronto.edu!rutgers!dptg!att!cbnewsl!dfp
From: dfp@cbnewsl.ATT.COM (david.f.prosser)
Newsgroups: comp.lang.c
Subject: Re: Atomic #defines (was Re: Password checking program)
Message-ID: <1706@cbnewsl.ATT.COM>
Date: 31 Aug 89 15:18:20 GMT
References: <10867@smoke.BRL.MIL>
Reply-To: dfp@cbnewsl.ATT.COM (david.f.prosser)
Organization: AT&T Bell Laboratories
Lines: 15

In article <10867@smoke.BRL.MIL> gwyn@brl.arpa (Doug Gwyn) writes:
>In article <13899@bloom-beacon.MIT.EDU> scs@adam.pika.mit.edu (Steve Summit) writes:
>>	#if EOF != -2
>
>This assumes more than the standard guarantees about EOF.
>In particular, EOF might be defined as an enumeration constant.
>That's unlikely, but permitted.

My reading of the pANS says that EOF must be a macro defined in <stdio.h>.
However, the integral constant expression that EOF is replaced by may well
involve operators or operands that are not valid in #if directives.  The
pANS has certain macros whose replacement expression are required to be
valid #if expression, so this was not an oversight.

Dave Prosser	...not an official X3J11 answer...