scons hierarchcal builds: propagating builders

Question

I need to be able to tune a construction environment so that I can either build a static or a shared objects in lower levels. Currently, I came up with the following approach:

top-level SConstruct:

if build_shared:
    env.Replace(ObjectBuilder = env.SharedObject)
    env.Replace(LibraryBuilder = env.SharedLibrary)
else:
    env.Replace(ObjectBuilder = env.StaticObject)
    env.Replace(LibraryBuilder = env.StaticLibrary)

and in lower-level SConstructs I invoke them by name:

env['ObjectBuilder']('foo.c')
env['LibraryBuilder']('lib', objects)

However, I'm not sure how sound this solution is. Is there a more straightforward/proper way to achieve the same functionality?

Thanks in advance.

Answer 1

The easiest way is to declare your own wrapper for env.Library() that simply passes its parameters to either env.StaticLibrary() or env.SharedLibrary().

Depending on whatever construction variable/scons option, you can have that wrapper alternate between the two.

def MyLibraryWrapper(self, *args, **kwargs):
  if self['BUILD_SHARED']:
    return self.SharedLibrary(*args, **kwargs)
  else:
    return self.StaticLibrary(*args, **kwargs)

env.SetDefault(BUILD_SHARED = False)
env.AddMethod(MyLibraryWrapper)

Make sure that snippet is your SConstruct, before any SConscript is parsed. To make it extra clean, create a tool in site_scons/site_tools and load it using env.Tool().