1CMP0119 2------- 3 4.. versionadded:: 3.20 5 6:prop_sf:`LANGUAGE` source file property explicitly compiles as specified 7language. 8 9The :prop_sf:`LANGUAGE` source file property is documented to mean that the 10source file is written in the specified language. In CMake 3.19 and below, 11setting this property causes CMake to compile the source file using the 12compiler for the specified language. However, it only passes an explicit 13flag to tell the compiler to treat the source as the specified language 14for MSVC-like, XL, and Embarcadero compilers for the ``CXX`` language. 15CMake 3.20 and above prefer to also explicitly tell the compiler to use 16the specified language using a flag such as ``-x c`` on all compilers 17for which such flags are known. 18 19This policy provides compatibility for projects that have not been updated 20to expect this behavior. For example, some projects were setting the 21``LANGUAGE`` property to ``C`` on assembly-language ``.S`` source files 22in order to compile them using the C compiler. Such projects should be 23updated to use ``enable_language(ASM)``, for which CMake will often choose 24the C compiler as the assembler on relevant platforms anyway. 25 26The ``OLD`` behavior for this policy is to interpret the ``LANGUAGE <LANG>`` 27property using its undocumented meaning to "use the ``<LANG>`` compiler". 28The ``NEW`` behavior for this policy is to interpret the ``LANGUAGE <LANG>`` 29property using its documented meaning to "compile as a ``<LANG>`` source". 30 31This policy was introduced in CMake version 3.20. Use the 32:command:`cmake_policy` command to set it to ``OLD`` or ``NEW`` explicitly. 33Unlike many policies, CMake version |release| does *not* warn 34when this policy is not set and simply uses ``OLD`` behavior. 35 36.. include:: DEPRECATED.txt 37