什么是特定的std :: bind的返回数据类型？ [英] What exactly is the returned data type for a particular std::bind?

问题描述

首先我必须说我必须知道从std :: bind返回的数据类型。

First I have to say I have to know the returned data type from std::bind.

我有一个结构体，定义为

I have a struct which is defined as

typedef struct
{
  UINT ID;
  CString NAME;
  boost::any Func;// 'auto' doesn't work here
} CALLBACK;
CALLBACK CallBackItems[];

Func是一个函数持有者，我想让它持有不同类型的回调函数。

Func is a function holder, I want it to hold different kinds of callback function.

我在这里初始化CallBackItems：

Somewhere I initialize CallBackItems like this:

CallBackItems[] =
{       
    { 1,    L"OnReady",       std::bind(&CPopunderDlg::OnReady, pDlg)           },
    { 2,    L"CustomFunction",std::bind(&CPopunderDlg::OnFSCommond, pDlg,_1,_2) }   
   //...................    more items here         
};

当我尝试在每个CALLBACK中使用'Func'时，它像一个函数。到目前为止我试过：

When I try to use the 'Func' in each CALLBACK I have to cast it first and then use it like a function. So far I tried:

 //CallBackItems[0].Func is binded from pDlg->OnReady(), pDlg->OnReady() works here,
   boost::any_cast<function<void()>>(CallBackItems[0].Func)();

   ((std::function<void()>)(CallBackItems[0].Func))();

它们都不工作，任何人都知道如何从std :: bind转换返回的变量？ p>

none of them work, anybody knows how to cast the returned variables from std::bind?

推荐答案

std :: bind 返回的类型未指定：

20.8.9.1.3函数模板bind [func.bind.bind]

sup> 1 ...

template< class F，class ... BoundArgs> br>
未指定 bind（F& f，BoundArgs& ... bound_args） ;

您可以使用 std :: function 以存储它们，例如

You can use std::function to store them, e.g.

void f( int ) {}
std::function< void(int) > f2 = std::bind(&f, _1);

在你的情况下，这意味着你可能需要转换类型当你存储结果从 std :: bind ：

In your case, this mean you could need to cast the type when you store the result from std::bind:

CallBackItems[] =
{     
    { 1, L"OnReady", std::function< void() >( std::bind(&CPopunderDlg::OnReady, pDlg) ) },
    { 2, L"CustomFunction", std::function< void(int,int) >( std::bind(&CPopunderDlg::OnFSCommond, pDlg,_1,_2) ) },                  
};

，然后取回：

boost::any_cast<std::function<void()>>(CallBackItems[0].Func)();

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