[CMake] Adding a generated file as a dependency to a target

[Michael Hertling]

On 01/27/2012 06:41 PM, Schuchard, Matthew wrote:
> Contrary to the CMake FAQ, but consistent with what I have been reading elsewhere, it does not seem possible for me with CMake 2.8.6 to add a generated file as a dependency to a target, even in the same directory.
> 
> I have done something similar to the following:
> 
> add_custom_command(OUTPUT foo.ext)
> add_executable(foo foo2.ext)
> add_custom_target(foo_custom DEPENDS foo.ext)
> set_source_files_properties(foo.ext PROPERTIES GENERATED TRUE)
> add_dependencies(foo foo_custom)
> 
> The above will not cause a dependency of foo on foo.ext, and when attempting to run make, throws an error of:
> No rule to make target 'CMakeFiles/foo_custom.dir/requires'
> 
> Could anyone please shine some light on this?
> What I have been reading elsewhere (CMake mailing list, stackoverflow, etc.) is that the majority of the time, attempting something similar to the above does not succeed.
> Could this fix be included among 2.8.8 updates?

Is foo2.txt in ADD_EXECUTABLE() a typo? Could you provide a minimal but
complete example which exposes your issue for detailed investigation?

The DEPENDS clause of custom targets/commands should always be used
with *full* paths, even if the concerned files are generated in the
same CMakeLists.txt, since the behavior w.r.t. relative paths isn't
specified. So, you might retry with DEPENDS ${CMAKE_CURRENT_BINARY_
DIR}/foo.ext. Besides, the GENERATED property doesn't need to be set
on files generated by ADD_CUSTOM_COMMAND(OUTPUT ...) as this is done
automatically.

Regards,

Michael