# CMP0019

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()`.

Do not re-expand variables in include and link information.

CMake 2.8.10 and lower re-evaluated values given to the include_directories, link_directories, and link_libraries commands to expand any leftover variable references at the end of the configuration step. This was for strict compatibility with VERY early CMake versions because all variable references are now normally evaluated during CMake language processing. CMake 2.8.11 and higher prefer to skip the extra evaluation.

The `OLD` behavior for this policy is to re-evaluate the values for strict compatibility. The `NEW` behavior for this policy is to leave the values untouched.

This policy was introduced in CMake version 2.8.11. 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.