C++提升绑定值类型

发布于 2024-08-31 00:20:32 字数 592 浏览 7 评论 0原文

我查看文档和源代码，但无法弄清楚如何获取 boost 绑定函子的返回值类型。我试图完成以下任务：

 35 template<typename T,size_t N, class F>
 36 boost::array<typename F::value_type, N> make_array(T (&input)[N], F unary) {
 37     boost::array<typename F::value_type, N> array;
 38     std::transform(input, input + N, array.begin(), unary);
 39     return array;
 40 }

其中 F 可以是绑定函子。上面的方法不起作用，因为函子没有 value_type。就此而言，就返回值而言，是否存在一元/二元函子的标准接口。

解决方案：它应该是result_type。对于二进制函数，还定义了等效的 argument_type 和 first/second_argument_type

谢谢

原文

I look in documentation and source code but cannot figure out how to get return value type of boost bind functor.
I am trying to accomplish following:

 35 template<typename T,size_t N, class F>
 36 boost::array<typename F::value_type, N> make_array(T (&input)[N], F unary) {
 37     boost::array<typename F::value_type, N> array;
 38     std::transform(input, input + N, array.begin(), unary);
 39     return array;
 40 }

where F can be bind functor. the above does not work because functor does not have value_type. for that matter, is there standard interface for unary/binary functor as far as return value.

solution: it should be result_type. also equivalent defined are argument_type and first/second_argument_type for binary functions

Thanks

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