| 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:: STANDARD_ADVICE.txt |
| |
| .. include:: DEPRECATED.txt |