[Boost-build] An option to prepend paths to %PATH% before executing a test built with a toolset

Subject: [Boost-build] An option to prepend paths to %PATH% before executing a test built with a toolset
From: Ion Gaztañaga (igaztanaga_at_[hidden])
Date: 2015-10-19 18:47:13

Hi,

Forgive me if this was previously solved, I couldn't find anything about 
this in the archives.

I'm trying to setup several mingw targets for my regression tests. I'd 
like to run several mingw installations (each one with a different 
compiler and runtime DLLs) in a single b2 invocation (apart from 
simplifying things, it maximizes CPU as it parallelizes all toolsets 
automatically).

In the different Mingw installations, I need to adjust the path before 
executing a test, as the DLLs needed for each toolset reside in 
different directories.

I've tried to modify "testing.jam" where the rule "run-path-setup" seems 
to do something similar with an option named "dll-path". However, I 
could not figure out how to pass a "compiler option" setting from a 
toolset to the "properties *" variable in rule "run-path-setup".

The basic idea is:

1) Define in a toolset, a path to be searched for DLLs before executing 
an executable compiled with that toolset:

using gcc : 4.3 : : <run-dll-paths>"C:/Programs/mingw-gcc-4.3/bin" ;

2) Propagate that option into the $(properties) passed to 
"capture-output" and similar rules

3) Obtain that path in "run-path-setup":

local run-dll-paths = [ feature.get-values <run-dll-paths> : 
$(properties) ] ;

4) Prepend it to PATH_SETUP

I've tried to hack it myself trying to imitate other rules, but after a 
couple of hours I just gave up with. Any similar feature that I might be 
missing? Any hint on how this can be implemented (I really know very 
little about Boost.Build)? Is this feature useful enough to add it to 
Boost.Build?

Best,

Ion