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From: rhg@cpsolv.UUCP (Richard H. Gumpertz)
Newsgroups: comp.os.os2,comp.lang.c,comp.std.c
Subject: Re: MSC __STDC__ strange value
Message-ID: <461@cpsolv.UUCP>
Date: 5 Dec 89 18:47:47 GMT
References: <223@bohra.cpg.oz>
Reply-To: rhg@cpsolv.uucp (Richard H. Gumpertz)
Organization: Computer Problem Solving, Leawood, Kansas
Lines: 26

In article <223@bohra.cpg.oz> ejp@bohra.cpg.oz (Esmond Pitt) writes:
>For some strange reason, the MSC 5.1 compiler defines __STDC__ as 0, so
...
>Why?

On page "Update-54" the manual entry for __STDC__ reads:
	The integer constant 0.  If equal to 1, this macro indicates
	full compliance with the ANSI proposed standard for the C
	programming language.
I suspect Microsoft extrapolated from the standard's definition of __STDC__
in which future versions may define values such as 2, 3, etc. to mean revised
C standards.  They extrapolated backward to 0, meaning close to but not fully
compliant.  A plausible (but strange) hack I suppose.

By the way, there is an interesting anomaly: The standard cannot say anything
about whether __STDC__ is defined or what its value should be for non-conforming
implementations -- it controls only the value for conforming ones!  Hence,
defining __STDC__ in a non-conforming implementation is perfectly legal so
long as conformance is not claimed elsewhere.  Of course, no sane implementor
of a non-conforming compiler should define it as 1 (or greater, I suppose)
unless he wants unhappy customers.  Sigh.     :-)
-- 
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