CMake/Help/policy/CMP0164.rst

CMP0164
-------

.. versionadded:: 3.30

:command:`add_library` rejects ``SHARED`` libraries when not supported by
the platform.

In CMake 3.29 and below, on platforms that do not support shared libraries
(:prop_gbl:`TARGET_SUPPORTS_SHARED_LIBS` is false), the
:command:`add_library` command automatically converts ``SHARED`` libraries to
``STATIC`` libraries to help users build projects on such platforms.  However,
the semantics of shared and static libraries are different enough that such
automatic conversion cannot work in general.  Projects using shared libraries
need to be ported to such platforms on a case-by-case basis.

In CMake 3.30 and above, :command:`add_library` prefers to reject creation
of shared libraries on platforms that do not support them, and fail with a
fatal error message.  This policy provides compatibility for projects that
happened to work with the automatic conversion to static libraries and have
not been updated with an explicit port.

The ``OLD`` behavior for this policy is to implicitly create a static
library with a developer warning.  The ``NEW`` behavior for this policy is
to fail.

.. |INTRODUCED_IN_CMAKE_VERSION| replace:: 3.30
.. |WARNS_OR_DOES_NOT_WARN| replace:: does *not* warn about the behavior change
.. include:: include/STANDARD_ADVICE.rst

.. include:: include/DEPRECATED.rst