C++警告类型胡枝子(* somename) (arg1，arg2)；

Question

首先..。我在一个名为core_ns.h的文件中有以下代码

/*
 * the prototype for the function that will be called when a connection
 * is made to a listen connection.  
 * Arguments:
 *    Server_Connection - ID of the listen connection that received the request
 *    New_Connection    - ID of the data connection that was created.
 */
typedef void (* CORE_NS_Connect_Callback)
                (CORE_NS_Connection_Type  Server_Connection,
                 CORE_NS_Connection_Type  New_Connection);

然后，我在一个名为ParameterServerCSC.h的文件中得到以下内容

class ParameterServer{
public:
    //-------------------------------------------------------------------------------
    //FUNCTION: sendCallback
    //
    //PURPOSE: This method will be performed upon a connection with the client. The 
    //Display Parameter Server will be sent following a connection.
    //-------------------------------------------------------------------------------
    void sendCallback (CORE_NS_Connection_Type serverConnection, CORE_NS_Connection_Type newConnection);
}; // end class ParameterServer

终于..。我在一个名为ParameterServer.cpp的文件中有以下用法

       //-------------------------------------------------------------------------------
      //FUNCTION: setup 
      //
      //PURPOSE: This method will perform any initialization that needs to be performed
      //at startup, such as initialization and registration of the server. 
      //-------------------------------------------------------------------------------
      void ParameterServer::setup(bool isCopilotMfd){

            CORE_NS_Connect_Callback newConnCallback; 
            newConnCallback = &ParameterServer::sendCallback;//point to local function to handle established connection.
      }

我收到以下警告：

警告:转换自void (ParameterServer::*)(CORE_NS_Connection_Type, CORE_NS_Connection_Type)' tovoid (*)(CORE_NS_Connection_Type，CORE_NS_Connection_Type)‘ MY_PROJECT/DisplayParameterServer ParameterServerCSC.cpp

我使用LynxOS178 178-2.2.2/GCC C++ compilier。我的解决方案建立在这个警告之上。我正在努力理解这些警告的含义。对此的任何见解都是值得赞赏的。

Answer 1

ParameterServer::sendCallback是一个成员函数或方法(其类型为void (ParameterServer::*)(CORE_NS_Connection_Type, CORE_NS_Connection_Type))，因此不能用作函数(void (*)(CORE_NS_Connection_Type, CORE_NS_Connection_Type)类型)。

您需要使它成为一个静态成员函数：

static void sendCallback (CORE_NS_Connection_Type serverConnection, CORE_NS_Connection_Type newConnection);

否则(取决于调用约定)，当API调用sendCallback时，参数将被错误地设置并显示为不正确；至少隐藏的this参数将是垃圾。