A solution to the multiple inclusion problem

[Richard O'Keefe]

In article <2550110 at hpisod2.HP.COM>, decot at 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?