CMake generator full path

Normally it is not necessary to specify the path to the CMake generator backend, assuming the generator executable is on the system PATH. For special use cases such as testing CMake with different versions of a generator the generator executable absolute path may be specified via CMAKE_MAKE_PROGRAM. The absolute path to the generator is necessary or CMake will not find it.

Suppose a GitHub Actions Linux image has containing executable file “ninja”. Get the absolute path using realpath.

    - run: unzip

    - name: CMake configure
      run: cmake -G Ninja -DCMAKE_MAKE_PROGRAM=$(realpath ./ninja) -Bbuild