CMP0055

Strict checking for the break() command.

CMake 3.1 and lower allowed calls to the break() command outside of a loop context and also ignored any given arguments. This was undefined behavior.

The OLD behavior for this policy is to allow break() to be placed outside of loop contexts and ignores any arguments. The NEW behavior for this policy is to issue an error if a misplaced break or any arguments are found.

This policy was introduced in CMake version 3.2. CMake version 3.2.3 warns when the policy is not set and uses OLD behavior. Use the cmake_policy command to set it to OLD or NEW explicitly.