cpp compatiblity Unix/VMS

[Paul Lew]

>From article <792 at cernvax.UUCP>, by hjm at cernvax.UUCP (hjm):
> 
> #include foobar
> #include <foobar.h>
> 
> are not the same if foobar is  a  logical  name!   Using  logical
> names  allows  for greater flexibility in where include files are
> kept (you may not want them kept with all the others because of a
> name  conflict, or perhaps you just want to be tidy), whereas the
> <foobar.h> form is an absolute address.
> 

Is there a version of cpp that will use Unix environment variables for
include file names?  This is something I like to have for a long time.

The imake utility ditributed with X11 uses cpp symbols as the include
file names. You may do something like:

	#ifdef	vms
	#else
	#define	foobar <foobar>
	#endif

	#include foobar

This works for BSD, 3B2, and Xenix systems.  I like it because you can
do things like:

	#ifdef	BSD
	#define	String_h	<strings.h>
	#else
	#define	String_h	<string.h>
	#endif

and put all these in one file.  There is no need to do #ifdef in every
C files!!  However, this works only if there is one to one mapping of
the inlcude file which unfortunately is not true for a lot of them. Any
remedy?
-- 
Paul Lew			{oliveb,harvard,decvax}!gsg!lew	(UUCP)
General Systems Group, 5 Manor Parkway, Salem, NH 03079	(603) 893-1000