From: Paul Shirley <Paul AT no DOT spam DOT please>
Newsgroups: comp.os.msdos.djgpp
Subject: Re: VBE Bankswitch in Pmode
Date: Fri, 13 Jun 1997 18:37:15 +0100
Organization: wot? me?
Distribution: world
Message-ID: <$6kKNHALVYozEwRV@foobar.co.uk>
References: <339C40FA DOT 15F9 AT piper DOT hamline DOT edu> <R6MBNFAX7YnzEwtn AT foobar DOT co DOT uk>
 <339F0269 DOT 6F93 AT cs DOT com>
Reply-To: Paul Shirley <Paul AT chocolat DOT obvious DOT fake DOT foobar DOT co DOT uk>
NNTP-Posting-Host: chocolat.foobar.co.uk
Mime-Version: 1.0
Lines: 18
To: djgpp AT delorie DOT com
DJ-Gateway: from newsgroup comp.os.msdos.djgpp
Precedence: bulk

In article <339F0269 DOT 6F93 AT cs DOT com>, "John M. Aldrich" <fighteer AT cs DOT com>
writes
>When I write my own header files and accidentally include them twice in
>the same source file, I get all sorts of errors about multiply defined
>constants and duplicate struct definitions and lots of other stuff. 
>Using the #ifndef __header_h__/#define __header_h__/.../#endif trick
>solves the problem perfectly.  Plus, it's the standard way to handle
>it.  What else could you ask for?

You misunderstood me.
The gmake docs claim that it will spot the #ifndef/#define sequence and
*not* even open the file the second time it gets #included. You still
need to add the exclusion of course.
The end result is that you no longer get any advantage from wrapping
header files externally as well as internally. (if it actually works ;)

---
Paul Shirley: my email address is 'obvious'ly anti-spammed