Path: utzoo!utgpu!news-server.csri.toronto.edu!cs.utexas.edu!uunet!world!madd
From: madd@world.std.com (jim frost)
Newsgroups: comp.unix.aix
Subject: Re: Bugs in RISC System/6000 C compiler
Keywords: bad macro substitution
Message-ID: <1990Sep21.191937.1289@world.std.com>
Date: 21 Sep 90 19:19:37 GMT
References: <9756@bunny.GTE.COM> <3824@segue.segue.com>
Organization: Saber Software
Lines: 32

jim@segue.segue.com (Jim Balter) writes:
>In article <9756@bunny.GTE.COM> hhd0@GTE.COM (Horace Dediu) writes:
>[ problems with macros ]

>The problem is most likely in your CAT macro, which probably looks like

>#define CAT(a,b)  a/**/b

>instead you should use

>#ifdef __STDC__
>#define CAT(a,b) a##b
>#else
>#define IDENT(x)x
>#define CAT(a,b)IDENT(a)b
>#endif

Yes, it depends on mode.  In `cc' mode (-qlanglvl=extended) the
old-style concatenation works.  In `xlc' mode (ANSI) you must use the
double-sharp.

Thus you can write:

#ifdef __STDC__
#define CAT(a,b) a##b
#else
#define CAT(a,b) a/**/b
#endif

jim frost
saber software
jimf@saber.com