Function invoke_r

dlib/functional.h:236–246

    template< typename R, typename F, typename... Args>
    constexpr typename std::enable_if<dlib::is_invocable_r<R, F, Args...>::value, R>::type
    invoke_r(F && f, Args &&... args)
    /*!
        ensures
            - identical to std::invoke_r<R>(std::forward<F>(f), std::forward<Args>(args)...)
            - works with C++11 onwards
    !*/
    noexcept(noexcept(dlib::invoke(std::forward<F>( f ), std::forward<Args>( args )...)))
    {
        return dlib::invoke(std::forward<F>( f ), std::forward<Args>( args )...);
    }

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