# CMP0002

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()`.

Logical target names must be globally unique.

Targets names created with `add_executable()`, `add_library()`, or `add_custom_target()` are logical build target names. Logical target names must be globally unique because:

- Unique names may be referenced unambiguously both in CMake code and on make tool command lines.

- Logical names are used by `Xcode` and Visual Studio IDE generators to produce meaningful project names for the targets.

The logical name of executable and library targets does not have to correspond to the physical file names built. Consider using the `OUTPUT_NAME` target property to create two targets with the same physical name while keeping logical names distinct. Custom targets must simply have globally unique names (unless one uses the global property `ALLOW_DUPLICATE_CUSTOM_TARGETS` with a Makefiles generator).

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.