Tell find_package() to try “Config” mode before “Module” mode if no mode was specified.

The command find_package() operates without an explicit mode when the reduced signature is used without the MODULE option. In this case, by default, CMake first tries Module mode by searching for a Find<pkg>.cmake module. If it fails, CMake then searches for the package using Config mode.

Set CMAKE_FIND_PACKAGE_PREFER_CONFIG to TRUE to tell find_package() to first search using Config mode before falling back to Module mode.

This variable may be useful when a developer has compiled a custom version of a common library and wishes to link it to a dependent project. If this variable is set to TRUE, it would prevent a dependent project’s call to find_package() from selecting the default library located by the system’s Find<pkg>.cmake module before finding the developer’s custom built library.

Once this variable is set, it is the responsibility of the exported <pkg>Config.cmake files to provide the same result variables as the Find<pkg>.cmake modules so that dependent projects can use them interchangeably.