CMP0039 — CMake 4.4.2 Documentation

# CMP0039

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()`.

Utility targets may not have link dependencies.

CMake 2.8.12 and lower allowed using utility targets in the left hand side position of the `target_link_libraries()` command. This is an indicator of a bug in user code.

The `OLD` behavior for this policy is to ignore attempts to set the link libraries of utility targets. The `NEW` behavior for this policy is to report an error if an attempt is made to set the link libraries of a utility target.

This policy was introduced in CMake version 3.0. 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.