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cmaketarget

How can I retrieve target properties from a CMake-generated buildsystem?

Suppose I have an existing project and it's cmake-configured build directory. How can I retreive some target's properties using this build, provided that I know the target name? I tried creating a separate script like this

get_target_property(VAR target property)

but it fails with error

Command get_target_property() is not scriptable

Are there any other methods?

Solution

  • Apparently get_target_property() can be called only when configuring a build directory with cmake. I am not aware of any method of getting targets properties on already configured build directory. But if modifying existing CMakeFiles.txt is an option, there is a workaround.

    You can try locating target definition, get the target's properties there and dump them into a text file. Then, this file can be then used in any other scripts called after build directory configuration is done.

    This example illustrates this workaround:

    add_executable(app ${app_sources}) 
set_target_properties(app PROPERTIES COMPILE_DEFINITIONS SOME_DEF=1)

get_target_property(compile_defs app COMPILE_DEFINITIONS)
file(WRITE app_compile_defs.txt ${compile_defs})

    Be sure to use get_target_property after every property changes for given target in CMakeFiles.txt are done. Otherwise you can miss something as in example below.

    add_executable(app ${app_sources}) 
set_target_properties(app PROPERTIES COMPILE_DEFINITIONS SOME_DEF=1)

get_target_property(compile_defs app COMPILE_DEFINITIONS)
file(WRITE app_compile_defs.txt ${compile_defs})

set_target_properties(app PROPERTIES COMPILE_DEFINITIONS ANOTHER_DEF=0)

    In the example above, the ANOTHER_DEF=0 definition will not be listed in app_compile_defs.txt.