cmake_minimum_required

Require a minimum version of cmake.

.. code-block:: cmake

cmake_minimum_required(VERSION <min>[...<policy_max>] [FATAL_ERROR])

.. versionadded:: 3.12 The optional <policy_max> version behavior; ignored in older CMake.

Sets the minimum required version of cmake for a project. Also updates the policy settings as explained below.

<min> and the optional <policy_max> are each CMake versions of the form major.minor[.patch[.tweak]], and the ... is literal.

If the running version of CMake is lower than the <min> required version it will stop processing the project and report an error. The optional <policy_max> version, if specified, must be at least the <min> version and sets the Policy Version_. If the running version of CMake is older than 3.12, the extra ... dots will be seen as version component separators, resulting in the ...<policy_max> part being ignored and preserving the pre-3.12 behavior of basing policies on <min>.

This command will set the value of the :variable:CMAKE_MINIMUM_REQUIRED_VERSION variable to <min>.

The FATAL_ERROR option is accepted but ignored by CMake 2.6 and higher. It should be specified so CMake versions 2.4 and lower fail with an error instead of just a warning.

.. note:: Call the cmake_minimum_required() command at the beginning of the top-level CMakeLists.txt file even before calling the :command:project command. It is important to establish version and policy settings before invoking other commands whose behavior they may affect. See also policy :policy:CMP0000.

Calling cmake_minimum_required() inside a :command:function limits some effects to the function scope when invoked. For example, the :variable:CMAKE_MINIMUM_REQUIRED_VERSION variable won't be set in the calling scope. Functions do not introduce their own policy scope though, so policy settings of the caller will be affected (see below). Due to this mix of things that do and do not affect the calling scope, calling cmake_minimum_required() inside a function is generally discouraged.

.. _Policy Version:

Policy Version ^^^^^^^^^^^^^^

cmake_minimum_required(VERSION <min>[...<policy_max>]) implicitly invokes

.. code-block:: cmake

cmake_policy(VERSION <min>[...<policy_max>])

.. include:: include/POLICY_VERSION.rst

.. include:: include/DEPRECATED_POLICY_VERSIONS.rst