CMP0204
-------

.. versionadded:: 4.2

A character set is always defined when targeting the MSVC ABI.

In CMake 4.1 and below, :ref:`Visual Studio Generators` compile sources in with
``_MBCS``, ``_UNICODE`` or ``_SBCS`` defined due to behavior of Visual Studio
itself.  The preprocessor definition is not modeled by CMake and is therefore
not added by other generators, such as :generator:`Ninja`.

CMake 4.2 and above, when targeting the MSVC ABI, prefer to compile sources
with ``_MBCS`` defined by all generators unless another charset preprocessor
definition is found (``_UNICODE`` or ``_SBCS``).
This policy provides compatibility with projects that have not been updated
to be aware of the definition.  Its setting is recorded by each target as
it is created, and affects compilation of sources in that target.

The ``OLD`` behavior for this policy does not model the ``_MBCS``
preprocessor definition in CMake itself.  The ``NEW`` behavior for this
policy adds the ``_MBCS`` preprocessor definition to sources
as a default encoding when targeting the MSVC ABI.

.. |INTRODUCED_IN_CMAKE_VERSION| replace:: 4.2
.. |WARNS_OR_DOES_NOT_WARN| replace:: does *not* warn
.. include:: include/STANDARD_ADVICE.rst

.. include:: include/DEPRECATED.rst