Create relocatable package with proper autogenerated config cmake - cmake

Question

I have created cmake target, say A, and want to install it and create a Config file, so that the installed package could be relocatable. My code is:
install(EXPORT ${PROJECT_NAME}Targets
FILE ${PROJECT_NAME}Targets.cmake
NAMESPACE ${PROJECT_NAME}::
DESTINATION ??? )
Here, I am having a problem with the proper destination. I want the Config file to be installed where ${CMAKE_INSTALL_PREFIX} points to. But when I put ${CMAKE_INSTALL_PREFIX} at ???, my resulting ATargets.cmake file contains the line:
set(_IMPORT_PREFIX "C:/Libraries/...")
which is the actual value of ${CMAKE_INSTALL_PREFIX}. This _IMPORT_PREFIX is later prepended to the parameters of set_target_properties() command inside the auto-generated ATargets.cmake, resulting in hard coded paths, valid only on the installation system.
I tried to use some generator expressions like <$IMPORT_PREFIX> in place of ???, but this gave me an error at cmake generation. I also tried to omit DESTINATION which in my opinion should place the file in the location relative to ${CMAKE_INSTALL_PREFIX}, but cmake complained about it too.
Can you please help me with this issue?

Answer 1

This is an old question so you have probably solved it already (or given up).
I think the critical thing is that the export DESTINATION matches the one given to INSTALL_DESTINATION to configure_package_config_file().
what we are using is:
install(TARGETS
foobar
EXPORT foobarLibTargets
LIBRARY DESTINATION lib)
set(ConfigFileInstallDir lib/cmake/foobar)
set(INCLUDE_INSTALL_DIR include)
set(LIBRARY_INSTALL_DIR lib)
configure_package_config_file(src/main/cmake/foobarConfig.cmake.in
"${CMAKE_CURRENT_BINARY_DIR}/foobarConfig.cmake"
INSTALL_DESTINATION "${ConfigFileInstallDir}"
PATH_VARS INCLUDE_INSTALL_DIR LIBRARY_INSTALL_DIR)
write_basic_package_version_file(
"${CMAKE_CURRENT_BINARY_DIR}/foobarConfigVersion.cmake"
VERSION "${VERSION}"
COMPATIBILITY ExactVersion)
export(EXPORT foobarLibTargets
FILE "${CMAKE_CURRENT_BINARY_DIR}/foobarLibTargets.cmake")
install(EXPORT foobarLibTargets
FILE foobarLibTargets.cmake
DESTINATION "${ConfigFileInstallDir}")
install(FILES
"${CMAKE_CURRENT_BINARY_DIR}/foobarConfig.cmake"
"${CMAKE_CURRENT_BINARY_DIR}/foobarConfigVersion.cmake"
"${CMAKE_CURRENT_BINARY_DIR}/foobarLibTargets.cmake"
DESTINATION "${ConfigFileInstallDir}")
${ConfigFileInstallDir} is replaced automagically by _IMPORT_PREFIX
so that the generated foobarLibTargets.cmake contains something like:
set_property(TARGET foobar APPEND PROPERTY IMPORTED_CONFIGURATIONS RELEASE)
set_target_properties(foobar PROPERTIES
IMPORTED_LOCATION_RELEASE "${_IMPORT_PREFIX}/lib/foobar.so.2.0.0"
IMPORTED_SONAME_RELEASE "libfoobar.so.2"
)
There can be troubles getting this to work. See my questions:
correctly set the location of imported cmake targets for an installed package &
Strange issue with variables in a config-file cmake package.
See you in the ward for those suffering from cmake related nervous disorders in the near future...