CMP0001

Warning

The OLD behavior of this policy was removed in CMake version 4.0. This policy must be set to NEW by a call to cmake_minimum_required() or cmake_policy().

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 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. Prior to removal in CMake version 4.0, it could be set by cmake_policy() or cmake_minimum_required(). If it was not set, CMake warned, and used OLD behavior.