具有类成员变量的 C++ 函数指针映射

Question

我正在尝试制作一个 STL 映射，键为“KEYWORD”，值为“类成员函数”，但它没有被编译。以下是代码。谁能告诉我出了什么问题。类成员函数不是静态的。

typedef void (RemoteHostManager::*CmdHandlerPtr)(char *);
typedef std::map<char *,CmdHandlerPtr> CommandHandlerSet;
typedef std::map<char *,CmdHandlerPtr>::iterator CommandHandlerSetItr;

void RemoteHostManager::InitializeCmdHandlerMap()
{
    m_CommandSet["HELP"]    = &RemoteHostManager::usage;
    m_CommandSet["CONNECT"] = &RemoteHostManager::Connect;
    m_CommandSet["READ"]    = &RemoteHostManager::Read;
    m_CommandSet["WRITE"]   = &RemoteHostManager::Write;
    m_CommandSet["STOP"]    = &RemoteHostManager::Stop;
    m_CommandSet["START"]   = &RemoteHostManager::Start;
}

错误如下:

RemoteHostManager.cpp: In member function `void
   RemoteHostManager::InitializeCmdHandlerMap()':
RemoteHostManager.cpp:14: no match for `std::_Rb_tree_iterator<std::pair<const
   std::string, void (RemoteHostManager::*)(char*)>, std::pair<const
   std::string, void (RemoteHostManager::*)(char*)>&, std::pair<const
   std::string, void (RemoteHostManager::*)(char*)>*>& [const char[5]]'
   operator
//similar error for other assignments!

Answer 1

typedef std::map<char *,CmdHandlerPtr> CommandHandlerSet;
typedef std::map<char *,CmdHandlerPtr>::iterator CommandHandlerSetItr;

首先让它成为const char*，或者更好的std::string:

typedef std::map<std::string,CmdHandlerPtr> CommandHandlerSet;
typedef std::map<std::string,CmdHandlerPtr>::iterator CommandHandlerSetItr;

请注意，您的所有成员函数都应与 CmdHandlerPtr 的类型相匹配。即参数类型必须是char*，返回类型必须是void。

使用 map 时，需要一个RemoteHostManager类型的实例:

RemoteHostManager instance;
string key;
//...
(instance.*m_CommandSet[key])(param);