Relay-Version: version B 2.10 5/3/83; site utzoo.UUCP
Path: utzoo!mnetor!uunet!husc6!mit-eddie!uw-beaver!teknowledge-vaxc!sri-unix!amdahl!oliveb!sun!gorodish!guy
From: guy@gorodish.Sun.COM (Guy Harris)
Newsgroups: comp.lang.c
Subject: Re: Preprocessor Portability
Message-ID: <33130@sun.uucp>
Date: Thu, 5-Nov-87 19:08:16 EST
Article-I.D.: sun.33130
Posted: Thu Nov  5 19:08:16 1987
Date-Received: Sun, 8-Nov-87 11:06:58 EST
References: <1986@killer.UUCP>
Sender: news@sun.uucp
Lines: 19

> A question on cpp:  how portable are "#elif" and "defined()"?  Although
> they aren't in K&R, I don't recall working on a system which doesn't
> have them.

Most C compilers using the Reiser "cpp", prior to the System V Release 3 C
compiler, do not have "#elif"; this means V7, System III, System V "Release 1"
and Release 2, and 4.[123]BSD.  Doug Gwyn has posted patches to put "#elif"
into older "cpp"s, but I suspect most systems out there do *not* have "#elif".

Most, if not all, C compilers with using the Reiser "cpp" have "defined()";
this means most UNIX C compilers will have it.

I can't speak for compilers not using the Reiser "cpp".

The current ANSI C draft specifies both, so all ANSI C-conformant C compilers
will have them unless they disappear in a future draft.
	Guy Harris
	{ihnp4, decvax, seismo, decwrl, ...}!sun!guy
	guy@sun.com