Date: Wed, 19 Jul 2000 14:25:53 -0400 (EDT)
Message-Id: <200007191825.OAA08689@indy.delorie.com>
From: Eli Zaretskii <eliz AT delorie DOT com>
To: martin AT loewis DOT home DOT cs DOT tu-berlin DOT de
CC: mrs AT windriver DOT com, gcc AT gcc DOT gnu DOT org, djgpp-workers AT delorie DOT com
In-reply-to: <200007181835.UAA00972@loewis.home.cs.tu-berlin.de>
	(martin AT loewis DOT home DOT cs DOT tu-berlin DOT de)
Subject: Re: GCC headers and DJGPP port
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> Date: Tue, 18 Jul 2000 20:35:44 +0200
> From: "Martin v. Loewis" <martin AT loewis DOT home DOT cs DOT tu-berlin DOT de>
> 
> I'm not talking about C, I'm talking about C++. If djgpp does not use
> __null for NULL, then it can't have the features that g++ has on other
> systems.

Sorry, my wording was inaccurate and misleading.  The problem is with
C++ programs that include <stdio.h> or <cstdio> (or stddef.h etc.)
after C++ headers such as <libio.h>: these define NULL, and GCC then
complains about its redifinition.

> I'm confused what question you are asking. Are you asking why GCC
> installs its headers?

It seems there has been a misunderstanding; I apologize for whatever
part of it that I'm responsible for.

Yes, the actual problem is that GCC installs its headers in a way that
cause them to be used before the system headers.  A related problem is
that GCC uses its own versions of stddef.h, limits.h, and other
headers instead of the system headers when GCC is built.  We were
worried that using headers that are different from the system headers
might produce buggy GCC binaries, due to conflicts with libc.a against
which the native DJGPP port is linked.

Our impression was that these two issues are connected, and that GCC
wants both to be built and used with its own versions of some of the
system headers.