[CMake] Adding multiple times the same target. How to make it clean ?

[Asmodehn Shade]

Hi everyone,

I have been using cmake for quite a while now. I am using 2.4.6 on NetBSD.
Among other things I do a dependency build automatically, based on a well-known directory
tree.

For example lets say you have :

CMakeLists.txt
Source1.c
depends/subprojA/
depends/subprojA/CMakeLists.txt - defining a new project that can be used separately.
depends/subprojA/SourceSubprojA.c

This works well.

My problem arise when I want to have two or more main targets ( lets say you add Source2.c to the previous example ) to get two executables using the same library for example.
The depends target gets cmake'd twice by the following code as expected ( simplified a lot because I do that in more complex generic cmake scripts ):

[...snip...]
MACRO (Build)
	FOREACH ( looparg ${ARGN} )
	
	GET_FILENAME_COMPONENT(exename ${looparg} NAME_WE )
	ADD_EXECUTABLE(${exename} ${looparg})
	ADD_SUBDIRECTORY(depends/subprojA depends/subprojA_build EXCLUDE_FROM_ALL)
	TARGET_LINK_LIBRARIES(${exename} subprojA)
	ADD_DEPENDENCIES(${exename} subprojA)

	ENDFOREACH ( looparg )
ENDMACRO (BuildDepends)
[...snip...]
FILE ( GLOB sourcelist ${CMAKE_SOURCE_DIR} *.c)
Build( ${sourcelist} )
[...snip...]

And cmake gives me lots of warnings :
make: "CMakeFiles/CMakeFiles/Makefile2" line 402: warning: duplicate script for target "depends/subprojA_build/CMakeFiles/subprojA.dir/all" ignored
make: "CMakeFiles/CMakeFiles/Makefile2" line 250: warning: using previous script for "depends/subprojA_build/CMakeFiles/subprojA.dir/all" defined here
Although it works ;)

What I need to do is : Not to do the ADD_SUBDIRECTORY if this subdirectory has just been cmaked, *_without_* taking the ADD_SUBDIRECTORY out of the loop or out of the macro of course ;)
My actual macro is more complex and provide a way to build and link custom dependencies only if needed. But I dont know how to check this dependency has been already made in this cmake call.
I just want to avoid the cmaking of it if possible, to avoid the warnings... The build will still run fine.

So I wonder if there is a way to check if a target has already been added ? how can I get the list of target ?
Can do a check on the subdirectory to make sure I just entered it for the first time in this " $ cmake sourcedir " call ?
Maybe another way to check something that will be enough so that I am assured that depends/subprojectA will be built once and once only if needed ?
I know I could build it manually, but I still want depends/subprojectA to build automatically with only one "cmake . && make" call

I can provide you with my cmake scripts, but I think it will be more of a trouble than a help to solve this little problem, probably coming of my lack of knowledge.
They are available here anyway if you want them : https://asmodehn.fr/trac/Workshop/browser/trunk/CMake although probably not the last version I am talking about here.
I hope I have been clear enough on my problem ;) Dont hesitate to ask me more questions if you want more informations.

Thank you very much for your help :)

--
Asmodehn