Path: utzoo!utgpu!news-server.csri.toronto.edu!clyde.concordia.ca!uunet!samsung!usc!jarthur!uci-ics!rfg
From: rfg@ics.uci.edu (Ronald Guilmette)
Newsgroups: comp.lang.c++
Subject: Re: Realized the error of my ways
Message-ID: <2611CC5B.16631@paris.ics.uci.edu>
Date: 29 Mar 90 08:50:35 GMT
References: <5790@rouge.usl.edu> <10625@alice.UUCP>
Reply-To: rfg@ics.uci.edu (Ronald Guilmette)
Organization: UC Irvine Department of ICS
Lines: 37

In article <10625@alice.UUCP> ark@alice.UUCP (Andrew Koenig) writes:
>In article <5790@rouge.usl.edu>, ewe@gator.cacs.usl.edu (Edwin Wallace Elberson) writes:
>
>>  I've got it straightened out now; I guess the problem was with my concept
>> of definitions and declarations. However, after seeing what I was trying to
>> do, does anyone have any tips on including the same header in files that
>> are to be compiled at the same time? Being new to C++, I'd like to see what
>> other people do in this situation, and how their techniques differ from
>> the way I'm doing it now. Thanks,
>
>The short answer is:
>
>	Suppose you have a class Foo that you want to use in
>	several separately compiled parts of your program.
>
>	Create a file called Foo.h that looks like this:
>
>		#ifndef Foo_flag
>		#define Foo_flag 1
>
>			other stuff goes here
>
>		#endif

Or, if you happen to be using the GNU g++ compiler (with the GNU preprocessor),
and you are not too worried about ANSI-C compatibility, you can use a little
feature that I invented (and implemented), to wit:

		#pragma once

When this appears in an include file, the preprocessor will not include
that particular file more than once during the current compilation.


// Ron Guilmette (rfg@ics.uci.edu)
// C++ Entomologist
// Motto:  If it sticks, force it.  If it breaks, it needed replacing anyway.