# CMAKE_POLICY_DEFAULT_CMP<NNNN>

Default for CMake Policy `CMP<NNNN>` when it is otherwise left unset.

Commands `cmake_minimum_required(VERSION)` and `cmake_policy(VERSION)` by default leave policies introduced after the given version unset. Set `CMAKE_POLICY_DEFAULT_CMP<NNNN>` to `OLD` or `NEW` to specify the default for policy `CMP<NNNN>`, where `<NNNN>` is the policy number.

This variable should not be set by a project in CMake code as a way to set its own policies; use `cmake_policy(SET)` instead. This variable is meant to externally set policies for which a project has not itself been updated:

- Users running CMake may set this variable in the cache (e.g. `-DCMAKE_POLICY_DEFAULT_CMP<NNNN>=<OLD|NEW>`). Set it to `OLD` to quiet a policy warning while using old behavior or to `NEW` to try building the project with new behavior.

- Projects may set this variable before a call to `add_subdirectory()` that adds a third-party project in order to set its policies without modifying third-party code.