CMake: How do I add a function to an installed config?

Question

I am creating a library which I am building and installing with CMake. In the CMakeLists.txt is install(TARGETS mylib ...) to install the library i

Answer 1

It is misconception that CMake should generate XXXConfig.cmake script. As opposite, intended behavior that CMake generates every other script (names can be any):

• XXXConfigTargets.cmake with install(EXPORT)
• XXXConfigVersion.cmake with write_basic_package_version_file()

and these scripts are included in the XXXConfig.cmake script written by hands, where you may define additional things:

# File: XXXConfig.cmake

include(${CMAKE_CURRENT_LIST_DIR}/XXXConfigVersion.cmake)
include(${CMAKE_CURRENT_LIST_DIR}/XXXConfigTargets.cmake)
# Here you may provide additional functions and other things.
function(my_func)
  ...
endfunction()

See more in the CMake packaging documentation.

Answer 2

To clarify further, there is a module that helps your configure valid and relocatable config file.

See macro configure_package_config_file provided by CMakePackageConfigHelpers module.

As mentioned by @Tsyvarev, the XXXConfig.cmake file should still be written by hand but configured with configure_package_config_file instead of configure_file.