Path: utzoo!utgpu!water!watmath!clyde!rutgers!im4u!woton!riddle
From: riddle@woton.UUCP (Prentiss Riddle )
Newsgroups: comp.lang.c
Subject: Re: Making re-#includes harmless--a simple solution?
Summary: But sometimes you *want* to #include a file multiple times
Message-ID: <1011@woton.UUCP>
Date: 10 Dec 87 17:00:52 GMT
References: <2000@bloom-beacon.MIT.EDU>
Organization: Shriners Burns Institute, Galveston
Lines: 16
Simply-Harmless: "Bob"

newman@athena.mit.edu (Ron Newman) writes:
> Why not change the semantics of "#include" to be:  "if, while
> processing the current .c source file, I have already included this
> file once, then don't include it again"?

But sometimes you *want* to #include a file multiple times.  One
example that comes to mind is the problem of generating essentially the
same code for multiple types of objects.  Redefine a few identifiers or
macros before each #inclusion and you've got it. 

One example of a program that does this trick is c_config, posted to
the net some time back by Steve Pemberton (steve@cwi.nl). 

--- Prentiss Riddle ("Aprendiz de todo, maestro de nada.")
--- Opinions expressed are not necessarily those of Shriners Burns Institute.
--- riddle@woton.UUCP  {ihnp4,harvard}!ut-sally!im4u!woton!riddle