[Boost-build] Convenient use of build and test semaphores

Subject: [Boost-build] Convenient use of build and test semaphores
From: Matthew Chambers (matt.chambers42_at_[hidden])
Date: 2010-09-09 15:55:24

  Hi,

I have a moderately large project with several hundred files and a couple hundred unit tests. We usually build on quad core machines with -j4. Some of our tests 
are I/O intensive and these should not run in parallel. We also have heuristic tests for thread-safety which are usually only effective when running alone 
(certainly not at the same time as any other thread-safety tests). The other tests run just fine in parallel. I don't think my case could be very unusual either.

So is there a good reason that the JAM_SEMAPHORE built-in is a pain in the ass to use (i.e. only usable on actualized targets AFAIK)? Shouldn't we be able to 
specify one or more optional semaphores as build requirements? There could be both build-time semaphores and runtime semaphores. The test semaphores would only 
apply at runtime (i.e. the unit-test and capture-output actions in testing.jam).

-Matt