documentation/scons_gotchas.txt

SCons gotchas
=============

Avoiding getting object files in the source tree
------------------------------------------------

If you use an absolute pathname in a source file list, SCons has the
annoying default behaviour of putting the resulting .o object file into the
source tree instead of into the build directory (under "scons-out").

For example, the following will do that:

# bad
env.ComponentLibrary('gtest',
                     ['${SOURCE_ROOT}/testing/gtest/src/gtest-all.cc'])

The workaround, which we use in various places, is to use ComponentObject()
to override the .o filename.  For example:

# good
env.ComponentLibrary(
    'gtest',
    [env.ComponentObject('gtest-all.o',
                         '${SOURCE_ROOT}/testing/gtest/src/gtest-all.cc')])

This fixed version avoids the problem of gtest-all.c getting rebuilt when
switching between the x86-32 and x86-64 builds.