https://github.com/Kitware/CMake
Tip revision: 554ebf643dfad2eb6877c3d5530b005cee453513 authored by Brad King on 08 July 2021, 13:46:27 UTC
CMake 3.21.0-rc3
CMake 3.21.0-rc3
Tip revision: 554ebf6
PROJECT_IS_TOP_LEVEL.rst
PROJECT_IS_TOP_LEVEL
--------------------
.. versionadded:: 3.21
A boolean variable indicating whether :command:`project` was called in a top
level ``CMakeLists.txt`` file.
Some modules should only be included as part of the top level
``CMakeLists.txt`` file to not cause unintended side effects in the build
tree, and this variable can be used to conditionally execute such code. For
example, consider the :module:`CTest` module, which creates targets and
options:
.. code-block:: cmake
project(MyProject)
...
if(PROJECT_IS_TOP_LEVEL)
include(CTest)
endif()
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`