Re: [jamboost] Pitfall -- environment variables

From: Richard Hadsell (hadsell_at_[hidden])
Date: 2002-03-28 10:49:46

David Abrahams wrote:
> 
> Your ideas are excellent. However, we're trying not to do too much more
> work on Boost.Build v1 and we /really/ hope that v2 will rely much less
> on environment variables. Of course, it seems likely to me that we'll
> still use some environment variables to do default configuration (e.g.
> detecting the OS). We'll be sure to document a method to find out what
> configuration the build system thinks it's got, and a method for
> explicitly telling it what configuration it should have.
> 
> How doesn that sound?

That sounds like a major improvement. In my case, however, even when it built a
bin.digital directory, I didn't recognize any problem. It was only when the
build failed with incorrect command options and I noticed bin.irix2, that I
realized my own OS was conflicting with Jam's usage.

Regardless of how you decide to control the build with environment variables, I
recommend (as did Rene Rivera) that you name them all with BOOST_ or JAM_, so
that their purpose is clear and less likely to conflict with a user's own
environment. You could ask the user to prefix all his own env variables, but
that's not very user friendly.

If you want to make the transition to new variable names less painful, you could
accept OS in the absence of JAM_OS, but then eventually discontinue use of OS.

-- 
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