_IS_TOP_LEVEL --------------------------- .. versionadded:: 3.21 A boolean variable indicating whether the named project was called in a top level ``CMakeLists.txt`` file. To obtain the value from the most recent call to :command:`project` in the current directory scope or above, see the :variable:`PROJECT_IS_TOP_LEVEL` variable. The variable value will be true in: * the top-level directory of the project * the top-level directory of an external project added by :module:`ExternalProject` The variable value will be false in: * a directory added by :command:`add_subdirectory` * a directory added by :module:`FetchContent`