# CMP0211

Added in version 4.4.

A file may belong to at most one non-`HEADERS` file set in a target.

In CMake 4.3 and below, it was possible to specify the same file in multiple file sets in a target. In CMake 4.4 and above, a file may belong to at most one file set in a target except for the `HEADERS` file set type. This policy provides compatibility for projects that have not been updated accordingly.

The `OLD` behavior for this policy is to accept the same file in multiple file sets in a target. The `NEW` behavior for this policy is to accept a given file in at most one file set in a target except for the `HEADERS` file set type.

This policy was introduced in CMake version 4.4. It may be set by `cmake_policy()` or `cmake_minimum_required()`. If it is not set, CMake warns when a file is part of multiple file sets in a target, and uses `OLD` behavior.

Note

The `OLD` behavior of a policy is deprecated by definition and may be removed in a future version of CMake.