Help/policy/CMP0000.rst

CMP0000
-------

A minimum required CMake version must be specified.

CMake requires that projects specify the version of CMake to which
they have been written.  This policy has been put in place so users
trying to build the project may be told when they need to update their
CMake.  Specifying a version also helps the project build with CMake
versions newer than that specified.  Use the :command:`cmake_minimum_required`
command at the top of your main ``CMakeLists.txt`` file:

::

  cmake_minimum_required(VERSION <major>.<minor>)

where ``<major>.<minor>`` is the version of CMake you want to support
(such as ``3.14``).  The command will ensure that at least the given
version of CMake is running and help newer versions be compatible with
the project.  See documentation of :command:`cmake_minimum_required` for
details.

Note that the command invocation must appear in the ``CMakeLists.txt``
file itself; a call in an included file is not sufficient.  However,
the  :command:`cmake_policy` command may be called to set policy ``CMP0000``
to ``OLD`` or ``NEW`` behavior explicitly.  The ``OLD`` behavior is to
silently ignore the missing invocation.  The ``NEW`` behavior is to issue
an error instead of a warning.  An included file may set ``CMP0000``
explicitly to affect how this policy is enforced for the main
``CMakeLists.txt`` file.

This policy was introduced in CMake version 2.6.0.

.. include:: DEPRECATED.txt