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CMP0149
-------
.. versionadded:: 3.27
:ref:`Visual Studio Generators` select latest Windows SDK by default.
Visual Studio Generators select a Windows SDK version to put in the
``WindowsTargetPlatformVersion`` setting in ``.vcxproj`` files.
CMake sets the :variable:`CMAKE_VS_WINDOWS_TARGET_PLATFORM_VERSION`
variable to the selected SDK version.
Prior to CMake 3.27, the SDK version was always selected by the value of
the :variable:`CMAKE_SYSTEM_VERSION` variable. Users or toolchain files
could set that variable to one of the exact Windows SDK versions available
on the host system. Since :variable:`CMAKE_SYSTEM_VERSION` defaults to
:variable:`CMAKE_HOST_SYSTEM_VERSION`, and it is not guaranteed that a
matching Windows SDK version is available, CMake had to fall back to
using the latest Windows SDK version if no exact match was available.
This approach was problematic:
* The latest Windows SDK might or might not be selected based on whether
the host version of Windows happens to match an available SDK version.
* An old Windows SDK version might be selected that has not been updated
for newer language standards such as C11.
CMake 3.27 and higher prefer to ignore the exact value of
:variable:`CMAKE_SYSTEM_VERSION` and by default select the latest SDK
version available. An exact SDK version may be specified explicitly
using a ``version=`` field in the :variable:`CMAKE_GENERATOR_PLATFORM`
variable. See :ref:`Visual Studio Platform Selection`.
This policy provides compatibility for projects, toolchain files, and
build scripts that have not been ported away from using
:variable:`CMAKE_SYSTEM_VERSION` to specify an exact SDK version.
.. note::
This policy must be set before the first :command:`project` or
:command:`enable_language` command invocation at the top of the
project. That is when :ref:`Visual Studio Generators` select a
Windows SDK.
The ``OLD`` behavior for this policy is to use the exact value of
:variable:`CMAKE_SYSTEM_VERSION` if possible. The ``NEW`` behavior
for this policy is to ignore it.
.. |INTRODUCED_IN_CMAKE_VERSION| replace:: 3.27
.. |WARNS_OR_DOES_NOT_WARN| replace:: does *not* warn
.. include:: include/STANDARD_ADVICE.rst
.. include:: include/DEPRECATED.rst
|
