CMake/Help/policy/CMP0001.rst

CMP0001
-------

``CMAKE_BACKWARDS_COMPATIBILITY`` should no longer be used.

The behavior is to check ``CMAKE_BACKWARDS_COMPATIBILITY`` and present
it to the user.  The ``NEW`` behavior is to ignore
CMAKE_BACKWARDS_COMPATIBILITY completely.

In CMake 2.4 and below the variable ``CMAKE_BACKWARDS_COMPATIBILITY`` was
used to request compatibility with earlier versions of CMake.  In
CMake 2.6 and above all compatibility issues are handled by policies
and the :command:`cmake_policy` command.  However, CMake must still check
``CMAKE_BACKWARDS_COMPATIBILITY`` for projects written for CMake 2.4 and
below.

This policy was introduced in CMake version 2.6.0.  CMake version
|release| warns when the policy is not set and uses ``OLD`` behavior.  Use
the :command:`cmake_policy` command to set it to ``OLD`` or ``NEW`` explicitly.

.. include:: DEPRECATED.txt