<PROJECT-NAME>_IS_TOP_LEVEL — CMake 4.2.6 Documentation

# <PROJECT-NAME>_IS_TOP_LEVEL

Added in version 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 `project()` in the current directory scope or above, see the `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 `ExternalProject`

- a directory added by `add_subdirectory()` that does not also contain a `project()` call

- a directory added by `FetchContent_MakeAvailable()`, if the fetched content does not contain a `project()` call

The variable value will be false in:

- a directory added by `add_subdirectory()` that also contains a `project()` call

- a directory added by `FetchContent_MakeAvailable()`, if the fetched content contains a `project()` call