Macro __cplusplus Macro __cplusplus Macro __cplusplus

    Use Case: Check Compiler Setting Check Compiler Setting

    #ifndef __cplusplus #error C++ is required #elif __cplusplus > 199711 // C++11 (or newer) code goes here #else // old-school code goes here #endif

    ISO Standard Values

    C++98 #define __cplusplus   199711
    C++11 #define __cplusplus   201103
    C++14 #define __cplusplus   201402
    C++17 #define __cplusplus   201703
    C++20 #define __cplusplus   202002

    Compiler Specifics

    Older Compilers

    If a compiler was released between C++ standards, values for __cplusplus might differ from the ones in the table above. However, you can always rely on the fact that the value of __cplusplus for a newer standard will be strictly larger than that of the previous standard.

    Microsoft Visual Studio (MSVC)

    • used to use non-standard conforming values
    • compiler switch /Zc:__cplusplus (as of Visual Studio 2017 version 15.7) makes MSVC use the standard values

    GCC (g++), Clang (clang++)

    use mostly standard conforming values for __cplusplus.

    Last updated: 2021-04-25

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