[CMake] Build one target with multiple subdirectories

[Michael Hammer]

Hi!

I would like to add a library and the sources are distributed in 
different directories, something like the following example:

/ CmakeLists.txt
  hello.cpp
  subdir1 / hello1.cpp
            hello2.cpp
            CMakeLists.txt
  subdir2 / hello3.cpp
            hello4.cpp
            CMakeLists.txt

In the CMakeLists.txt of subdir1 I would write:

set( subdir1_SOURCES
     hello1.cpp
     hello2.cpp )

similar in subdir2

set( subdir2_SOURCES
     hello3.cpp
     hello4.cpp )

in /CMakeLists.txt I would add something like that:

add_subdirectory(subdir1)
add_subdirectory(subdir2)

add_library( irgendwas
             hello.cpp
             subdir_1/${subdir1_SOURCES}
             subdir_2/${subdir2_SOURCES} )

Unfortunately this doesn't work ;) CMake doesn't set the variables 
subdirx_SOURCES by calling add_subdirectory. The next problem I see is 
the add_library statement. In subdir1_SOURCES there is a necessary path 
prefix (subdir1/, subdir2/) missing - I am really not sure if I can add 
the prefix the way I have done it here (obviously not ;)).

Perhaps someone can help? I am sure there is a "good" or "accurate" way 
to do this - thanks a lot.

Michael

-- 
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Dipl.-Ing. (MSc) Michael Hammer (Scientific Assistant)     __  _|  |_
Institute for Strength of Materials /                     |  ||      |
           Graz University of Technology                  |_    _||__|
phone: +43 (0) 316 873 / 7667                               |__|
fax:   +43 (0) 316 873 / 7169
http://www.fest.TUGraz.at/                    michael.hammer at tugraz.at
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