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From: terry@cs.weber.edu (Terry Lambert)
Message-Id: <9505031725.AA14847@cs.weber.edu>
Subject: Re: GNU cpp bug with pthreads
To: bde@zeta.org.au (Bruce Evans)
Date: Wed, 3 May 95 11:25:50 MDT
Cc: j@uriah.heep.sax.de, rpt@miles.sso.loral.com, hackers@FreeBSD.org
In-Reply-To: <199505030717.RAA31389@godzilla.zeta.org.au> from "Bruce Evans" at May 3, 95 05:17:33 pm
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> >> #ifdef __STDC__
> 
> >Note: this should be ``#if __STDC__'' anyway.  Some preprocessors do
> >define this macro to 0 when running in `traditional' mode.  ANSI says
> >it is ``the constant 1'' in a standard-conforming environment.
> 
> The FreeBSD headers (include and sys) consistently use `#ifdef __STDC__'
> It makes no difference in a standard conforming environment but `ifdef'
> may be more likely to DTRT for quasi-standard environments.

The Sun "transitional compiler" #defines __STDC__ as 0 in non-ANSI mode
and as 1 in ANSI mode.

The use of #if resolves the potential problems, while #ifdef does not.

On the other hand, #if is not necessarily a valid directive in older
preprocessers.

So you end up doing weenie things, first looking for the definition then
looking at the value.


					Terry Lambert
					terry@cs.weber.edu
---
Any opinions in this posting are my own and not those of my present
or previous employers.