Ways to specify [[nodiscard]] before C++17

I need the semantics of the [[nodiscard]] attribute in a non-C++17 codebase. I guess there are compiler dependent ways of achieving this before C++17. Does anyone know these? I am interested in the ones for clang,gcc, and MSVC.

• GCC/Clang: __attribute__((warn_unused_result))
• MSVC: _Check_return_ for _MSC_VER >= 1700 (Visual Studio 2012)