enable_language

Enable a language (CXX/C/Fortran/etc)

enable_language(<lang> [OPTIONAL] )

This command enables support for the named language in CMake. This is the same as the project command but does not create any of the extra variables that are created by the project command. Example languages are CXX, C, CUDA, Fortran, and ASM.

If enabling ASM, enable it last so that CMake can check whether compilers for other languages like C work for assembly too.

This command must be called in file scope, not in a function call. Furthermore, it must be called in the highest directory common to all targets using the named language directly for compiling sources or indirectly through link dependencies. It is simplest to enable all needed languages in the top-level directory of a project.

The OPTIONAL keyword is a placeholder for future implementation and does not currently work. Instead you can use the CheckLanguage module to verify support before enabling.