Pitfall -- environment variables

From: Richard Hadsell (hadsell_at_[hidden])
Date: 2002-03-27 14:17:43

In trying to figure out why I was having problems builing Jam on my Irix system, I discovered a
pitfall that was causing them. I have OS set to IRIX2 (don't bother asking why) in my environment,
so it was overriding what Jam would like to see -- IRIX. The same was actually occurring on my
Tru64 system, where I had OS = DIGITAL instead of OSF, but the defaults were o.k. there.

I would recommend that Jam or Boost show up front somewhere in the Build instructions a list of all
relevant environment variables. If the list is too long to document each one, you could just name
them, and you could indicate that everything matching BOOST_* is reserved.

Of course, variables starting with BOOST are not a problem, but generic ones like OS are. You might
consider becoming less dependent on the user's environment. For instance, you might let the user
override the self-determination of OS only on the command line and not with an environment variable.

I don't want to upset your basic approach, especially if you have strong opinions about how you want
the user to set up his environment. However, you should at least document with some obvious caveats
what you expect from the environment. Many of us have been customizing our environments for a long
time and have good reasons for doing so.

-- 
Dick Hadsell	914-259-6320 Fax: [phone]
Reply-to:	hadsell_at_[hidden]
Blue Sky Studios http://www.blueskystudios.com
44 South Broadway, White Plains, NY 10601