Help/policy/CMP0137.rst

CMP0137
-------

.. versionadded:: 3.24

:command:`try_compile` passes platform variables in project mode.

The :command:`try_compile` command :ref:`source file <Try Compiling Source
Files>` signature propagates CMake variables containing platform settings,
and those specified by the :variable:`CMAKE_TRY_COMPILE_PLATFORM_VARIABLES`
variable, into the generated test project.  This helps the test project drive
the toolchain the same way the calling project will.  In CMake 3.23 and below,
the :ref:`whole-project <Try Compiling Whole Projects>` signature does not
propagate platform variables automatically.  CMake 3.24 and above prefer to
propagate platform variables in the :ref:`whole-project <Try Compiling Whole
Projects>` signature.  This policy provides compatibility with projects that
have not been updated to expect the behavior.

The ``OLD`` behavior for this policy is to not pass any additional variables to
the :ref:`whole-project <Try Compiling Whole Projects>` signature.
The ``NEW`` behavior for this policy is to pass the same variables that the
:ref:`source file <Try Compiling Source Files>` signature does.

This policy was introduced in CMake version 3.24.  Use the
:command:`cmake_policy` command to set this policy to ``OLD`` or ``NEW``
explicitly. Unlike many policies, CMake version |release| does *not* warn
by default when this policy is not set and simply uses ``OLD`` behavior.

.. include:: DEPRECATED.txt