# cmake_minimum_required

Set the minimum required version of cmake for a project.

    cmake_minimum_required(VERSION major[.minor[.patch[.tweak]]]
                           [FATAL_ERROR])

If the current version of CMake is lower than that required it will stop processing the project and report an error. When a version higher than 2.4 is specified the command implicitly invokes

    cmake_policy(VERSION major[.minor[.patch[.tweak]]])

which sets the cmake policy version level to the version specified. When version 2.4 or lower is given the command implicitly invokes

    cmake_policy(VERSION 2.4)

which enables compatibility features for CMake 2.4 and lower.

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 `project()` command. It is important to establish version and policy settings before invoking other commands whose behavior they may affect. See also policy `CMP0000`.

Calling `cmake_minimum_required()` inside a `function()` limits some effects to the function scope when invoked. Such calls should not be made with the intention of having global effects.