cpp compatiblity Unix/VMS

[Richard A. O'Keefe]

In article <134 at iquery.UUCP> matt at iquery.UUCP (Matt Reedy) writes:
>The problem is the following:  I want the same source to compile on both
>SysV and VMS, so I use this style:
>#ifdef VAX
>#include file
>#include stdio
>#else
>#include <fcntl.h>
>#include <stdio.h>
>#endif
>[V.3 cpp dislikes the first two #includes]

(1) That should be #ifdef vms, not #ifdef VAX.  VAXen run 4.?BSD, Ultrix,
    and some flavour of System V, as well as VMS.

(2) While
	#include stdio
    and	#include <stdio.h>
    do mean different things in VAX-11 C (check the manual) the latter form
    _is_ accepted and will work unless you've gone out of your way to break
    it.  You should be able to convert to

	#ifdef vms
	#include <file.h>
	#include <stdio.h>
	#else
	#include <fcntl.h>
	#include <stdio.h>
	#endif

    and have it work on both.  (We had to do this for quite a lot of files;
    what makes it particularly galling is that the vms #includes caused no
    trouble in V.2.  Sometimes I wonder about AT&T.)

(3) Another possibility is to use some other preprocessor.  For example,
    stuff your program through the GNU "C Compatible Compiler
    Preprocessor (CCCP)", and give the result to AT&T's compiler.