如何使用升压绑定一个成员函数 [英] How to use boost bind with a member function
问题描述
以下code使CL.EXE崩溃(MS VS2005)。结果
我想使用升压绑定来创建一个函数来调用一个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()\n"); }
void fun2(int i) { printf("fun2(%d)\n", 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;
}
我在做什么错了?
What am I doing wrong?
推荐答案
使用以下代替:
boost::function<void (int)> f2( boost::bind( &myclass::fun2, this, _1 ) );
此转发传递给函数的对象使用占位函数的第一个参数 - 你要告诉的 Boost.Bind 的如何处理的参数。随着你的前pression它会尝试跨preT它为不接受参数的成员函数。结果
例如参见这里 或的这里常见的使用模式。
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.
注意VC8s CL.EXE定期的 Boost.Bind 的误用崩溃 - 如果有疑问,使用测试用例与海湾合作委员会,你可能会得到很好的提示类的模板参数绑定的-internals用,如果你通过输出读取实例化。
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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