Enable languages (CXX/C/OBJC/OBJCXX/Fortran/etc)

enable_language(<lang>... [OPTIONAL])

Enables support for the named languages 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.

Supported languages are C, CXX (i.e. C++), CSharp (i.e. C#), CUDA, OBJC (i.e. Objective-C), OBJCXX (i.e. Objective-C++), Fortran, HIP, ISPC, Swift, ASM, ASM_NASM, ASM_MARMASM, ASM_MASM, and ASM-ATT.

New in version 3.8: Added CSharp and CUDA support.

New in version 3.15: Added Swift support.

New in version 3.16: Added OBJC and OBJCXX support.

New in version 3.18: Added ISPC support.

New in version 3.21: Added HIP support.

New in version 3.26: Added ASM_MARMASM support.

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

The following restrictions apply to where enable_language() may be called:

  • It must be called in file scope, not in a function call.

  • It must not be called before the first call to project(). See policy CMP0165.

  • 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.