提高::绑定与默认值的成员函数？ [英] boost::bind for a member function with default value?

问题描述

struct A
{
  A(int v):value(v){}
  int someFun(){return value;}
  int someOtherFun(int v=0){return v+value;}
  int value;
};

int main()
{
    boost::shared_ptr<A> a(new A(42));
    //boost::function<int()> b1(bind(&A::someOtherFun,a,_1)); //Error
    boost::function<int()> b2(bind(&A::someFun,a));
    b2();
    return 0;
}

绑定（安培; A :: someOtherFun，A）（）; 失败，编译错误：错误：无效使用非静态成员函数

如何绑定someOtherFun类似someFun？即，应结合相同的boost ::功能类型。

How to bind someOtherFun similar to the someFun? i.e, they should bind to the same boost::function type.

推荐答案

A :: someFun（）和 A :: someOtherFun（）有不同的类型：第一希望没有参数，第二个预计1（可ommitted和编译器插入defaqult值你）

A::someFun() and A::someOtherFun() have different types: the first expects no parameters, the second expects 1 (which can be ommitted and the compiler inserts the defaqult value for you)

尝试：

bind(&A::someOtherFun, a, _1)(1);

问题是，当你调用通过功能绑定（），编译器不知道有该绑定功能的默认参数值，从而为您提供了错误因为你不具备所需的参数

The problem is that when you call the function via bind(), the compiler does not know there is a default parameter value for that bound function and thus gives you error because you don't have the required parameter

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