Function test_functions

dlib/test/invoke.cpp:64–141

    }

    void test_functions()
    {
        static_assert(dlib::is_invocable<decltype(func_testargs), int, std::string, const std::string&, const std::string&, std::string&>::value, "should be invocable!");
        static_assert(dlib::is_invocable<decltype(func_testargs), int, std::string, std::string, const std::string&, std::string&>::value, "should be invocable!");
        static_assert(dlib::is_invocable<decltype(func_testargs), int, std::string, std::string, std::string, std::string&>::value, "should be invocable!");
        static_assert(dlib::is_invocable<decltype(func_testargs), int, std::string, std::string, std::string, std::reference_wrapper<std::string>>::value, "should be invocable!");
        static_assert(dlib::is_invocable<decltype(func_return_addition), int, int>::value, "should be invocable!");
        static_assert(dlib::is_invocable_r<float, decltype(func_return_addition), int, int>::value, "should be invocable_r!");
        static_assert(!dlib::is_invocable_r<std::string, decltype(func_return_addition), int, int>::value, "should be invocable_r!");

        static_assert(std::is_same<dlib::callable_args<decltype(func_testargs)>,
                                   dlib::types_<int, std::string, const std::string&, const std::string&, std::string&>
                                   >::value, "make this correct");
        
        static_assert(dlib::callable_nargs<decltype(func_testargs)>::value == 5, "bad");

        static_assert(std::is_same<dlib::callable_arg<0, decltype(func_testargs)>,
                                   int>::value, "make this correct");
        
        static_assert(std::is_same<dlib::callable_arg<1, decltype(func_testargs)>,
                                   std::string>::value, "make this correct");

        static_assert(std::is_same<dlib::callable_arg<2, decltype(func_testargs)>,
                                   const std::string&>::value, "make this correct");

        static_assert(std::is_same<dlib::callable_arg<3, decltype(func_testargs)>,
                                   const std::string&>::value, "make this correct");

        static_assert(std::is_same<dlib::callable_arg<4, decltype(func_testargs)>,
                                   std::string&>::value, "make this correct");

        static_assert(std::is_same<dlib::callable_return<decltype(func_testargs)>,
                                   void>::value, "make this correct");

        static_assert(is_callable<decltype(func_testargs)>::value, "bad");

        static_assert(std::is_same<dlib::callable_args<decltype(func_return_addition)>,
                                   dlib::types_<int, int>
                                   >::value, "make this correct");
        
        static_assert(dlib::callable_nargs<decltype(func_return_addition)>::value == 2, "bad");

        static_assert(std::is_same<dlib::callable_arg<0, decltype(func_return_addition)>,
                                   int
                                   >::value, "make this correct");

        static_assert(std::is_same<dlib::callable_arg<1, decltype(func_return_addition)>,
                                   int
                                   >::value, "make this correct");

        static_assert(std::is_same<dlib::callable_return<decltype(func_return_addition)>,
                                   int>::value, "make this correct");
        
        static_assert(is_callable<decltype(func_return_addition)>::value, "bad");

        {
            std::string str = run1_str4;
            dlib::invoke(func_testargs, 1, run1_str1, run1_str2, std::cref(run1_str3), std::ref(str));