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From: ok@cs.mu.oz.au (Richard O'Keefe)
Newsgroups: comp.lang.c
Subject: Re: A solution to the multiple inclusion problem
Message-ID: <2552@munnari.oz.au>
Date: 27 Oct 89 13:49:14 GMT
References: <14240@well.UUCP> <2550110@hpisod2.HP.COM>
Sender: news@cs.mu.oz.au
Lines: 18

In article <2550110@hpisod2.HP.COM>, decot@hpisod2.HP.COM (Dave Decot) writes:
> > Why does everybody feel compelled to reinvent this wheel?
> Because there's no STANDARD (**HINT**) way to do it that has any
> hope of efficiency!!

But we've been shown several.  The simplest is the two-files-per-header
method:
	your file		foo.h			foo1.h

	#include "foo.h"	#ifndef FOO_H		/* whatever */
				#define FOO_H 1
				#include "foo1.h"
				#endif

You can apply this technique even when foo1.h is a header file supplied
by someone else:  foo.h gets rescanned every time but this is file
open + file close + reading four lines, and the #pragma once hack saves
you just the cost of reading three lines.  Big saving, huh?