[CMake] scope of set_source_files_properties?

[Simmons, Aaron]

I'm having trouble using set_source_files_properties from a subdirectory.  Say I have a top-level CMakeLists.txt like this:
        cmake_minimum_required(VERSION 2.8)
        project(test)
        add_subdirectory(subdir)
        get_source_file_property( temp subdir/test.c COMPILE_FLAGS )
        message("reading property from toplevel= ${temp}")

and I have a subdir/CMakeLists.txt like this:
        set_source_files_properties( subdir/test.c PROPERTIES COMPILE_FLAGS "-DBLAHBLAH")
        get_source_file_property( temp subdir/test.c COMPILE_FLAGS )
        message("reading property from subdir= ${temp}")

then the output of cmake will be:
        reading property from subdir= -DBLAHBLAH
        reading property from toplevel= NOTFOUND

Are source file properties inherently local scope?  Is there any way to specify the scope (like you can for the "set" function)?



Thanks,
aaron