Xref: utzoo comp.lang.c:32707 comp.unix.questions:26047
Path: utzoo!attcan!uunet!know!samsung!umich!yale!cmcl2!adm!smoke!gwyn
From: gwyn@smoke.BRL.MIL (Doug Gwyn)
Newsgroups: comp.lang.c,comp.unix.questions
Subject: Re: C Compiler under Unix System VR4
Message-ID: <14056@smoke.BRL.MIL>
Date: 8 Oct 90 13:13:22 GMT
References: <125@alfrat.uucp>
Followup-To: comp.lang.c
Organization: U.S. Army Ballistic Research Laboratory, APG, MD.
Lines: 20

In article <125@alfrat.uucp> roy@alfrat.UUCP (Roy Phillips) writes:
-The standard header files supplied with AT&T's UNIX System V Release 4.2
-contains pre-processor commands such as the following:
-   #if #machine(pdp11)
-The C preprocessor supplied has no problems with this, but my preferred C
-compiler, gcc, objects, even in it's '-ansi' mode.  So I guess it's
-not ANSI C.  

Correct -- This is a nonstandard extension, and any program using it
is not strictly conforming, meaning that it may be rejected by some
other (standard conforming) C compiler.

-My questions are::
-1. Does anyone know about this pre-processor syntax? and is it
-   supposed to be standard on SysVR4?

Yes, in fact I think this was added around SVR3.2.

In my option, it was ill-conceived, and hinders application portability
rather than enhancing it.