[CMake] Preventing add_custom_command from removing output

[Alain Miniussi]

Hi,

I have a source file (version.cpp) I need to generate trough a script.

What the script does is

- generate a version.cpp.new file
- if version.cpp does not exists or is different from version.cpp.new, 
copy version.cpp.new into version.cpp

-------------------

add_custom_command(OUTPUT version.cpp always
   COMMAND
   bash -x ${CMAKE_SOURCE_DIR}/tools/dev/gen_version.sh 
${CMAKE_CURRENT_BINARY_DIR}/version.cpp  )

set_source_files_properties(version.cpp PROPERTIES GENERATED TRUE)

-----------------

the 'always' target is here to make sure the script is alway called (in 
case the version changed).

Unfortunately, it seems that add_custom_command will delete its output 
before calling the command. As a result the version.cpp's dependancies 
are always bult.

Is there a way to prevent that deletion ?


Thanks

-- 
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Alain Miniussi
DSI, Pôles Calcul et Genie Log.
Tél. : +33492003009 (Mont-Gros)
Tél. : +33483618544 (Sophia Antipolis)