CMake module to easily play with compile flags by seamlessly detecting their availability and carefully setting them target by target.
To use FlagManager.cmake, simply add this repository as git submodule into your own repository
mkdir externals
git submodule add https://github.com/rbost/cmake-flag-manager.gitand adding externals/cmake-flag-manager/cmake to your CMAKE_MODULE_PATH
list(APPEND CMAKE_MODULE_PATH "${CMAKE_SOURCE_DIR}/externals/cmake-flag-manager/cmake")You can also simply copy the FlagManager.cmake file in your repo. However, these will not be updated without re-copying the file.
Finally, include the FlagManager package, say in the root CMake file, by add the following lines:
find_package(FlagManager)The FlagManager package defines two functions: save_compile_option to save compile options, and target_apply_saved_options to apply previously saved options.
Use save_compile_option to add a new compile options. This function will check if the option is available for either your C or your C++ compiler, and save it to a language-specific list of compile options. The function can be passed a list of options, in which case, the availability of the options will be tested consecutively, in the given order:
save_compile_option(-Wall -Wextra)Note that, by default, the availability of the flag will be checked for both the C and C++ compilers.
If you want to only check a flag on the C++ compiler, use the CXX_ONLY option:
save_compile_option(CXX_ONLY -Weffc++)Several option lists can be used, so to support multiple configurations for multiple targets.
To save an option to a specific list, use the LIST_NAME option:
save_compile_option(LIST_NAME "Errors" -Werror)The target_apply_saved_options function is used to apply the saved options to a list of targets:
target_apply_saved_options(MyLib MyExe)To apply a specific option list, use the LIST_NAME option as follows:
target_apply_saved_options(LIST_NAME "Errors" MyLib)This CMake module is released under the MIT license. See the LICENSE file for more information.