Re: [Boost-build] Creating a configuration rule?

Subject: Re: [Boost-build] Creating a configuration rule?
From: Vladimir Prus (ghost_at_[hidden])
Date: 2008-11-03 01:26:52

On Saturday 01 November 2008 21:15:45 John Maddock wrote:
> OK here's the issue:
> 
> In Boost.Math I have some library binaries, and some tests that should only 
> be built if some feature X is present (say long double support for example).
> 
> So... I can make those targets depend upon an "obj" rule that builds the 
> feature-test program.  Now those targets only get built if the feature is 
> supported, which is a lot better than 1000's of meaningless error 
> messages... but,
> 
> What I would really prefer is for the tests and libraries to get a <build>no 
> property if the feature test fails to compile, that way I won't see all 
> those "skipping target X for lack of Y" messages.  I'd also like the feature 
> test failure to be quiet, so it doesn't get reported as an error at the end.
> 
> Is any of this possible?

Not at the moment. To perform "clean" skipping of a target you have to build/run
a configuration test before a main target is converted into bjam targets, and
right now, we first convert everything in bjam targets and then build -- and
at that point there are not properties, and pretty much nothing else but files.

I'm planning to address this issue as part of my "bjam configure" work I plan 
to do after 1.37 is out.

- Volodya