IMPORTED_GLOBAL

Indication of whether an IMPORTED target is globally visible.

The boolean value of this property is True for targets created with the IMPORTED GLOBAL options to add_executable() or add_library(). It is always False for targets built within the project.

For targets created with the IMPORTED option to add_executable() or add_library() but without the additional option GLOBAL this is False, too. However, setting this property for such a locally IMPORTED target to True promotes that target to global scope. This promotion can only be done in the same directory where that IMPORTED target was created in the first place.

Once an imported target has been made global, it cannot be changed back to non-global. Therefore, if a project sets this property, it may only provide a value of True. CMake will issue an error if the project tries to set the property to a non-True value, even if the value was already False.