CMAKE_COMPILER_IS_GNUCXX

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Cmake/docs/3.21/variable/cmake compiler is gnucxx


CMAKE_COMPILER_IS_GNUCXX

New in version 3.7.


True if the C++ (CXX) compiler is GNU. Use CMAKE_CXX_COMPILER_ID instead.

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https://cmake.org/cmake/help/v3.21/variable/CMAKE_COMPILER_IS_GNUCXX.html