如何获取重载成员函数的地址？ [英] How to get the address of an overloaded member function?

问题描述

我试图获取指向特定版本的重载成员函数的指针。例如：

I'm trying to get a pointer to a specific version of an overloaded member function. Here's the example:

class C
{
  bool f(int) { ... }
  bool f(double) { ... }

  bool example()
  {
    // I want to get the "double" version.
    typedef bool (C::*MemberFunctionType)(double);
    MemberFunctionType pointer = &C::f;   // <- Visual C++ complains
  }
};

错误消息是error C2440：'initializing'：无法从'overloaded-function' 'MemberFunctionType'

The error message is "error C2440: 'initializing' : cannot convert from 'overloaded-function' to 'MemberFunctionType'"

如果 f 没有重载，任何建议？

This works if f is not overloaded, but not in the example above. Any suggestion?

请注意，上述代码并未反映出我的现实问题，我忘了一个常量 - 这是接受的答案指出。我会离开这个问题，因为我认为这个问题可能发生在别人身上。

Beware, the code above did not reflect my real-world problem, which was that I had forgotten a "const" - this is what the accepted answer points out. I'll leave the question as it is, though, because I think the problem could happen to others.

推荐答案

我会回答我所作的评论，所以它可以接受。问题是与constness：

Well, i'll answer what i put as comment already so it can be accepted. Problem is with constness:

class C
{
  bool f(int) { ... }
  bool f(double) const { ... }

  bool example()
  {
    // I want to get the "double" version.
    typedef bool (C::*MemberFunctionType)(double) const; // const required!
    MemberFunctionType pointer = &C::f;
  }
};

澄清：

原始问题不包含 const 。我在评论中做了一个疯狂的猜测，他是否可能有 f 作为一个const成员函数在真正的代码（因为在一个更早的迭代，结果还是另一件事缺少/不同于真实世界的代码：p）。他实际上是一个const成员函数，并告诉我，我应该发布为一个答案。

The original question didn't contain that const. I did a wild guess in the comments whether he possibly has f being a const member function in the real code (because at a yet earlier iteration, it turned out yet another thing was missing/different to the real-world code :p). He actually had it being a const member function, and told me i should post this as an answer.

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