Path: utzoo!utgpu!news-server.csri.toronto.edu!cs.utexas.edu!rice!hsdndev!cmcl2!kramden.acf.nyu.edu!brnstnd
From: brnstnd@kramden.acf.nyu.edu (Dan Bernstein)
Newsgroups: comp.sources.d
Subject: Re: Help define Environment: usage in c.s.m
Message-ID: <20585:Jun1203:03:5491@kramden.acf.nyu.edu>
Date: 12 Jun 91 03:03:54 GMT
References: <1991May26.041741.22210@sparky.IMD.Sterling.COM> <2088:Jun309:46:2191@kramden.acf.nyu.edu> <19359@rpp386.cactus.org>
Organization: IR
Lines: 34

In article <19359@rpp386.cactus.org> jfh@rpp386.cactus.org (John F Haugh II) writes:
> In article <2088:Jun309:46:2191@kramden.acf.nyu.edu>, brnstnd@kramden.acf.nyu.edu (Dan Bernstein) writes:
> > I don't think the point of an Environment line is to express exactly
> > which systems the package will run under. What's important is that it
> > say where the package *won't* run, so that people avoid downloading the
> > package if they won't be able to use it. So:
> > Environment: !SunOS<3.4, !SVR<3, !(Motif 1.1 & X11R3), ?!UNIX
> The abundance of !'s in your examples lead me to believe that you've
> not thought about this very hard.

You're right; in the three years I've been adding X-Context headers to
my postings, I haven't thought one bit about the number of exclamation
points.

Since the real purpose of the line is to keep people from wasting effort
on packages they won't get to use, it should be titled appropriately:

   Wont-Work-With: non-UNIX, SunOS<3.4, SVR<3, Motif 1.1 & X11R<4

That's about as simple as it can get for that set of requirements.

> Whereas if just about any POSIX compliant UNIX with BSD enhancements
> is likely to work, it would be
> 	Environment: POSIX && BSD

Again, the point of this line is for people (not your C compiler---what's
this && stuff?) to avoid bothering with a package that they can't use. It
should read like a set of danger signs:

   Wont-Work-With: non-POSIX, non-BSD

The first danger sign you hit, you get off the road.

---Dan