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From: jsdy@hadron.UUCP (Joseph S. D. Yao)
Newsgroups: net.unix-wizards
Subject: Re: Re(cap): Which Unix?
Message-ID: <179@hadron.UUCP>
Date: Mon, 6-May-85 23:32:29 EDT
Article-I.D.: hadron.179
Posted: Mon May  6 23:32:29 1985
Date-Received: Fri, 10-May-85 08:20:35 EDT
References: <237@dadla.UUCP>
Distribution: net
Organization: Hadron, Inc., Fairfax, VA
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> [No matter where you go..... there you are.  Buckaroo Banzai]
> 
> It seems to me that (when this was bandied about on the net
> a few weeks ago) there never was a EASY method for determining
> which version of UN*X a program was being compiled under.
> 	...
> What I'm proposing is for ALL UN*X systems to have a single
> (additional) include file: /usr/include/unix.h, which would
> contain something like:
> 		-Roger [Southwick]
> UUCP:			...!tektronix!dadla!rogers

Many but not all UNIces already have an include file <local/uparm.h>.
It does not bother to define a value for each type of UNIX, but just
tries to:
	#define	BSD4_1	/* N O T  BSD.4.1 !!! */
or
	#define SYSVR2
or whatnot, and then use:
	#ifdef	BSD4_1
		...
	#endif	BSD4_1	/* So who likes the ANSI restriction? */

Thus, you need not have a global update of all machines' uparm.h's:
just make sure that your symbol is a universally agreed-on one.
(What good is #ifdef BSD41 above?)  You may wish to define several
for particular things available on your machine (#define BSD4_2;
#define SCCS; #define RCS).

If you want to mess anybody who isn't in your list of machines:
	#ifdef	SYSVR1
		...
	# elif	BSD4_1	/* well, I do like most of ANSI. */
		...
	# else
		THIS WILL UPSET THE COMPILER!
	#endif	SYSTEMS			/* but not all. */

Anybody want to contribute the symbols for their machine that they
like best?

	Joe Yao		hadron!jsdy@seismo.{ARPA,UUCP}