Path: utzoo!attcan!utgpu!jarvis.csri.toronto.edu!rutgers!tut.cis.ohio-state.edu!gem.mps.ohio-state.edu!wuarchive!wugate!uunet!lotus!mgordon
From: mgordon@lotus.com (PCSD Mac)
Newsgroups: comp.lang.c
Subject: Re: A solution to the multiple inclusion problem
Keywords: #include c c++
Message-ID: <1989Oct24.153611.12168@lotus.com>
Date: 24 Oct 89 15:36:11 GMT
References: <14240@well.UUCP> <15316@bloom-beacon.MIT.EDU>
Reply-To: mgordon@lotus.UUCP (PCSD Mac)
Distribution: comp
Organization: Lotus Development Corp.
Lines: 11


How about a new preprocessor directive that means "include this file only 
if it hasn't already been included", say "#require"?  The "preprocessor"
would simply keep a table of files that have already been included and use 
it to avoid including the same #required file more than once.  There will 
always be files you really do want to #include multiple times, so you can't
change the meaning of #include.

I believe that would do the trick, and it wouldn't break any existing 
programs.  If you use this construct though, you can't go back to compilers 
that don't support it.