CMP0037

Target names should not be reserved and should match a validity pattern.

CMake 2.8.12 and lower allowed creating targets using add_library(), add_executable() and add_custom_target() with unrestricted choice for the target name. Newer cmake features such as cmake-generator-expressions(7) and some diagnostics expect target names to match a restricted pattern.

Target names may contain upper and lower case letters, numbers, the underscore character (_), dot(.), plus(+) and minus(-). As a special case, ALIAS and IMPORTED targets may contain two consecutive colons.

Target names reserved by one or more CMake generators are not allowed. Among others these include all, clean, help, and install.

Target names associated with optional features, such as test and package, may also be reserved. CMake 3.10 and below always reserve them. CMake 3.11 and above reserve them only when the corresponding feature is enabled (e.g. by including the CTest or CPack modules).

The OLD behavior for this policy is to allow creating targets with reserved names or which do not match the validity pattern. The NEW behavior for this policy is to report an error if an add_* command is used with an invalid target name.

This policy was introduced in CMake version 3.0. CMake version 3.19.0-rc3 warns when the policy is not set and uses OLD behavior. Use the cmake_policy() command to set it to OLD or NEW explicitly.