[CMake] Iterating over a generator expression list, specifically $<TARGET_OBJECTS:objlib> of an OBJECT library

[George PF]

Hello,

how can e.g. $<TARGET_OBJECTS:objlib> be iterated over in cmake?

This builds the lib, but the loop is never run:

    add_library(objlib12 OBJECT lib1.c lib2.c)
    foreach(o IN LISTS $<TARGET_OBJECTS:objlib12>)
        message("obj ${o}")
    endforeach()

But the $<TARGET_OBJECTS:objlib12> variable is set correctly, as this builds a shared library:

    add_library(lib12 SHARED $<TARGET_OBJECTS:objlib12>)

And the ;-separated list is visible when running this custom command via the 'test12' target:

    add_custom_command(OUTPUT libtest.cc
        COMMAND bash -c "echo '$<TARGET_OBJECTS:objlib12>'; echo > libtest.cc"
        VERBATIM)
    add_library(test12 SHARED libtest.cc)


Why does the for loop completely ignore this variable?


Regards

GPF