[CMake] add_custom_command doesn't know about target; but get_target_property does

[Nils Gladitz]

On 21.08.2014 22:27, Braden McDaniel wrote:
> I have the following code that executes in a top-level CMakeLists.txt 
> *after* having recursed into subdirectories:
>
>     get_target_property(TARGET_NAME ${EXPORT_TARGET} NAME)
>     message(STATUS "${EXPORT_TARGET} NAME = ${TARGET_NAME}")
>     add_custom_command(
>         TARGET ${EXPORT_TARGET} POST_BUILD
>         COMMAND ${CMAKE_COMMAND} -E echo $<TARGET_FILE> > 
> ${CMAKE_BINARY_DIR}/${LIB_PATHS}/${EXPORT_TARGET}_$<CONFIG>
>     )
>
> EXPORT_TARGET is a library target defined in a subdirectory.  This 
> results in the following output from CMake:
>
> my_target NAME = my_target
> CMake Warning (dev) at CMakeLists.txt:965 (add_custom_command):
>   Policy CMP0040 is not set: The target in the TARGET signature of
>   add_custom_command() must exist.  Run "cmake --help-policy CMP0040" for
>   policy details.  Use the cmake_policy command to set the policy and
>   suppress this warning.
>
>   The target name "my_target" is unknown in this context.
>
> How come get_target_property knows about the target but 
> add_custom_command does not?
>
> I am using CMake 3.0.1.
>

Custom commands can only be attached to targets defined in the current 
directory.

Nils