如何使用带有成员函数的 boost 绑定 [英] How to use boost bind with a member function

问题描述

以下代码导致 cl.exe 崩溃(MS VS2005).
我正在尝试使用 boost bind 创建一个函数来调用 myclass 的方法:

The following code causes cl.exe to crash (MS VS2005).
I am trying to use boost bind to create a function to a calls a method of myclass:

#include "stdafx.h"
#include <boost/function.hpp>
#include <boost/bind.hpp>
#include <functional>

class myclass {
public:
    void fun1()       { printf("fun1()
");      }
    void fun2(int i)  { printf("fun2(%d)
", i); }

    void testit() {
        boost::function<void ()>    f1( boost::bind( &myclass::fun1, this ) );
        boost::function<void (int)> f2( boost::bind( &myclass::fun2, this ) ); //fails

        f1();
        f2(111);
    }
};

int main(int argc, char* argv[]) {
    myclass mc;
    mc.testit();
    return 0;
}

我做错了什么?

推荐答案

改用以下内容:

boost::function<void (int)> f2( boost::bind( &myclass::fun2, this, _1 ) );

这使用占位符将传递给函数对象的第一个参数转发给函数 - 您必须告诉 Boost.Bind 如何处理这些参数.使用您的表达式，它会尝试将其解释为不带参数的成员函数.
见例如此处 或 此处了解常见的使用模式.

This forwards the first parameter passed to the function object to the function using place-holders - you have to tell Boost.Bind how to handle the parameters. With your expression it would try to interpret it as a member function taking no arguments.
See e.g. here or here for common usage patterns.

请注意，VC8s cl.exe 经常因 Boost.Bind 误用而崩溃 - 如果有疑问，请使用带有 gcc 的测试用例，您可能会得到很好的提示，例如模板参数 Bind<如果您通读输出，/em>-internals 会被实例化.

Note that VC8s cl.exe regularly crashes on Boost.Bind misuses - if in doubt use a test-case with gcc and you will probably get good hints like the template parameters Bind-internals were instantiated with if you read through the output.

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