Creating a Listening Socket

#include 
#include 
#include 

#define NETWORK_ERROR -1
#define NETWORK_OK     0

void ReportError(int, const char *);


int WINAPI WinMain(HINSTANCE hInst, HINSTANCE hPrevInst, LPSTR lpCmd, int nShow)
{
 WORD sockVersion;
 WSADATA wsaData;
 int nret;

 sockVersion = MAKEWORD(1, 1);   // We'd like Winsock version 1.1


 // We begin by initializing Winsock
 WSAStartup(sockVersion, &wsaData);


 // Next, create the listening socket
 SOCKET listeningSocket;

 listeningSocket = socket(AF_INET,  // Go over TCP/IP
            SOCK_STREAM,    // This is a stream-oriented socket
     IPPROTO_TCP);  // Use TCP rather than UDP

 if (listeningSocket == INVALID_SOCKET)
 {
  nret = WSAGetLastError();  // Get a more detailed error
  ReportError(nret, "socket()");  // Report the error with our custom function

  WSACleanup();    // Shutdown Winsock
  return NETWORK_ERROR;   // Return an error value
 }


 // Use a SOCKADDR_IN struct to fill in address information
 SOCKADDR_IN serverInfo;

 serverInfo.sin_family = AF_INET;
 serverInfo.sin_addr.s_addr = INADDR_ANY; // Since this socket is listening for connections,
       // any local address will do
 serverInfo.sin_port = htons(8888);  // Convert integer 8888 to network-byte order
       // and insert into the port field


 // Bind the socket to our local server address
 nret = bind(listeningSocket, (LPSOCKADDR)&serverInfo, sizeof(struct sockaddr));

 if (nret == SOCKET_ERROR)
 {
  nret = WSAGetLastError();
  ReportError(nret, "bind()");

  WSACleanup();
  return NETWORK_ERROR;
 }


 // Make the socket listen
 nret = listen(listeningSocket, 10);  // Up to 10 connections may wait at any
       // one time to be accept()'ed

 if (nret == SOCKET_ERROR)
 {
  nret = WSAGetLastError();
  ReportError(nret, "listen()");

  WSACleanup();
  return NETWORK_ERROR;
 }


 // Wait for a client
 SOCKET theClient;

 theClient = accept(listeningSocket,
      NULL,   // Optionally, address of a SOCKADDR_IN struct
      NULL);   // Optionally, address of variable containing
       // sizeof ( struct SOCKADDR_IN )

 if (theClient == INVALID_SOCKET)
 {
  nret = WSAGetLastError();
  ReportError(nret, "accept()");

  WSACleanup();
  return NETWORK_ERROR;
 }


 // Send and receive from the client, and finally,
 closesocket(theClient);
 closesocket(listeningSocket);


 // Shutdown Winsock
 WSACleanup();
 return NETWORK_OK;
}


void ReportError(int errorCode, const char *whichFunc)
{
   char errorMsg[92];     // Declare a buffer to hold
       // the generated error message
   
   ZeroMemory(errorMsg, 92);    // Automatically NULL-terminate the string

   // The following line copies the phrase, whichFunc string, and integer errorCode into the buffer
   sprintf(errorMsg, "Call to %s returned error %d!", (char *)whichFunc, errorCode);

   MessageBox(NULL, errorMsg, "socketIndication", MB_OK);
}