From owner-freebsd-current  Thu Nov  8  8:32:48 2001
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To: clefevre@citeweb.net
Subject: Re: malloc.h 
Cc: Joerg Wunsch <joerg_wunsch@uriah.heep.sax.de>,
	freebsd-current@FreeBSD.ORG
In-reply-to: Your message of "Thu, 08 Nov 2001 10:50:18 +0100."
		<200111080950.fA89oIk21059@gits.dyndns.org> 
References: <200111080950.fA89oIk21059@gits.dyndns.org>  
Date: Thu, 08 Nov 2001 09:32:35 -0700
From: Warner Losh <imp@harmony.village.org>
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In message <200111080950.fA89oIk21059@gits.dyndns.org> Cyrille Lefevre writes:
: Warner Losh wrote:
: > In message <20011108075021.P43204@uriah.heep.sax.de> Joerg Wunsch writes:
: > : > #if (__STDC__-0) == 0
: > : 
: > : What is the difference to my version (except that it would fail for
: > : __STDC__ being greater than 1)?  I don't know how pre-ANSI cpps did
: > : behave, but at least a standard-conformant cpp must replace any
: > : identifier in an #if statement that remains after macro expansion by
: > : 0L.
: 
: the difference is that if __STDC__ isn't defined, #if (-0)==0 continue
: to work.

No.  If __STDC__ isn't defined, the old K&R cpp will substitude 0.  At
least most unix, portable cc based ones do.  But I do see the utility
of the trick.

: also, as I remember me, Solaris or HP uses the construction I post
: in they headers.

Right.  But the solaris and HP compilers handled the

#if __STDC__

properly.  I've used it there several times since 1991 or so when I
ported OI to about 50 different machines.

Warner

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