Setting default compiler in CMake

With CMake version 3.15 or later, you can set the CMAKE_GENERATOR environment variable to specify the default generator to be used on your system.

You only have to set the toolchain/output format once, typically you'd do this upon running cmake for the first time:

cmake -G "MinGW Makefiles" .

Instead of the dot you can use your own parameters (if any) and/or the path to the source.

As an alternative, especially when you're new to CMake, use the GUI version under windows (run cmake-gui without parameters instead of cmake).

Once opened, set your paths and click on "Configure". If there's no compiler set, it will ask you to pick one (otherwise you have to clear the cache to make it reappear).

Updated configuration values will appear in red and it will also allow you to select files and paths using the common Windows dialog boxes.

Once configuration is complete and without errors you can hit "generate" to create your makefiles or project files. To update these later on, you can use cmake-gui again or just use the usual command line version cmake.

Under Windows CMake uses the newest Visual Studio installation as default generator, unless the generator is explicitly specified upon invoking CMake. This behavior is hard coded and cannot be changed.

As a work-around you can use a batch wrapper script titled cmake.bat with the following contents:

@cmake.exe -G "MinGW Makefiles" %*

The script should be placed in a directory on the system PATH and should take precedence over the CMake executable cmake.exe.

The script invokes cmake.exe with MinGW as a generator and forwards all other parameters to it.