Path: utzoo!mnetor!uunet!husc6!bbn!rochester!ritcv!cci632!ccicpg!nick
From: nick@ccicpg.UUCP (Nick Crossley)
Newsgroups: comp.lang.c
Subject: Re: CPP defines...
Message-ID: <14490@ccicpg.UUCP>
Date: 10 Mar 88 23:38:46 GMT
References: <14192@hc.DSPO.GOV> <179@istop.ist.CO.UK>
Reply-To: nick@ccicpg.UUCP (Nick Crossley)
Organization: CCI CPG, Irvine CA
Lines: 26
Keywords: cpp,preprocessor,#define

In article <179@istop.ist.CO.UK> rb@ist.CO.UK (News reading a/c for rb) writes:
>Here's a nasty little script that comes in useful when you
>want to know what your cpp *really* predefines: we have found
>that the man page is sometimes economical with the truth.
> ...
>strings -a -2 /lib/cpp | sed '/^a-zA-Z0-9_/!s/.*/#ifdef &\
>"%&"\
>#endif/p' |/lib/cpp |sed -n '/%/s/[%"]//gp'

Ah, but not all systems have their predefined symbols defined by cpp!  I know
of some which define some symbols in cc!  Thus, a better? more complete?
approach might be :-

strings <options as required> /lib/cpp /bin/cc |
sort -u |
sed -n '/^[a-zA-Z0-9_]*$/s//#ifdef &\
"%&"\
#endif/p' >cpp_test.c

cc -E cpp_test.c |
sed -n '/%/s/[%"]//gp'
-- 

<<< standard disclaimers >>>
Nick Crossley, CCI, 9801 Muirlands, Irvine, CA 92718-2521, USA
Tel. (714) 458-7282,  uucp: ...!uunet!ccicpg!nick