Debug vs Release in CMake

With CMake, it’s generally recommended to do an “out of source” build. Create your CMakeLists.txt in the root of your project. Then from the root of your project:

mkdir Release
cd Release
cmake -DCMAKE_BUILD_TYPE=Release ..
make

And for Debug (again from the root of your project):

mkdir Debug
cd Debug
cmake -DCMAKE_BUILD_TYPE=Debug ..
make

Release / Debug will add the appropriate flags for your compiler. There are also RelWithDebInfo and MinSizeRel build configurations.


You can modify/add to the flags by specifying a toolchain file in which you can add CMAKE_<LANG>_FLAGS_<CONFIG>_INIT variables, e.g.:

set(CMAKE_CXX_FLAGS_DEBUG_INIT "-Wall")
set(CMAKE_CXX_FLAGS_RELEASE_INIT "-Wall")

See CMAKE_BUILD_TYPE for more details.


As for your third question, I’m not sure what you are asking exactly. CMake should automatically detect and use the compiler appropriate for your different source files.

Leave a Comment