_IS_TOP_LEVEL
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Cmake/docs/3.21/variable/project-name is top level
_IS_TOP_LEVEL
New 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
The variable value will be false in:
- a directory added by add_subdirectory()
- a directory added by FetchContent
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Licensed under the BSD 3-clause License.
https://cmake.org/cmake/help/v3.21/variable/PROJECT-NAME_IS_TOP_LEVEL.html