Winsock Select模型范例

服务器端：
#include <Winsock2.h>
#include <stdio.h>

void InitSocket()
{
 WORD wVersionRequested;
 WSADATA wsaData;
 int err;

 wVersionRequested = MAKEWORD( 2, 2 );

 err = WSAStartup( wVersionRequested, &wsaData );
 if ( err != 0 ) {
  /* Tell the user that we could not find a usable */
  /* WinSock DLL.                                  */
  return;
 }

 /* Confirm that the WinSock DLL supports 2.2.*/
 /* Note that if the DLL supports versions greater    */
 /* than 2.2 in addition to 2.2, it will still return */
 /* 2.2 in wVersion since that is the version we      */
 /* requested.                                        */

 if ( LOBYTE( wsaData.wVersion ) != 2 ||
  HIBYTE( wsaData.wVersion ) != 2 ) {
   /* Tell the user that we could not find a usable */
   /* WinSock DLL.                                  */
   WSACleanup( );
   return;
  }
}
int main(int argc, char* argv[])
{
 InitSocket();
 SOCKET sock=::socket(AF_INET,SOCK_STREAM,0);
 if(sock==INVALID_SOCKET)
 {
  printf("创建socket失败");
  WSACleanup( );
  return 0;
 }
 //::sockaddr_in serAddr;
 SOCKADDR_IN serAddr;
 serAddr.sin_family=AF_INET;
 serAddr.sin_port=::htons(5150);
 serAddr.sin_addr.s_addr = htonl(INADDR_ANY);
 if(SOCKET_ERROR==bind(sock,(sockaddr*)&serAddr,sizeof(sockaddr)))
 {
  printf("绑定失败");
  WSACleanup( );
  return 0;
 }
 listen(sock,5);
 fd_set fdSocket;
 FD_ZERO(&fdSocket);
 FD_SET(sock,&fdSocket);
 while(true)
 {
  fd_set fdRead=fdSocket;
  int nRet=::select(0,&fdRead,NULL,NULL,NULL);
  if(nRet>0)
  {
   for(int i=0;i<(int)fdSocket.fd_count;i++)
   {
    if(FD_ISSET(fdSocket.fd_array[i],&fdRead))
    {
     //有新的连接到达
     if(fdSocket.fd_array[i]==sock)
     {
      if(fdSocket.fd_count<FD_SETSIZE)
      {
       ::sockaddr_in addr;
       int len=sizeof(sockaddr);
       SOCKET client=accept(sock,(sockaddr*)&addr,&len);
       printf("接收到新的连接 : %s/n",::inet_ntoa(addr.sin_addr));
       FD_SET(client,&fdSocket);
      }
      else
      {
       printf("too many connections/n");
      }
     }
     else
     {
      char*buf=new char[1024];
      int nRecv=::recv(fdSocket.fd_array[i],buf,1024,0);
      if(nRecv>0)
      {
       buf[nRecv]='/0';
       printf("收到数据: %s/n",buf);
      }
      else
      {
       ::closesocket(fdSocket.fd_array[i]);
       FD_CLR(fdSocket.fd_array[i],&fdSocket);
       printf("一客户端断开连接/n");
      }
      delete []buf;
     }
    }
   }
  }
 }
 return 0;
}

客户端：

#include <winsock2.h>
#include <stdio.h>
#include <memory.h>
#include <iostream>
#include <string>
using namespace std;

void main(int argc, char **argv)
{
 WSADATA              wsaData;
 SOCKET               s;
 SOCKADDR_IN          ServerAddr;
 int                  Port = 5150;
 int                  Ret, Ret1;
 string Data;
 char     DataServe[8];
 memset(DataServe, 0, 8);
 char pause;

 if (argc <= 1)
 {
  printf("USAGE: tcpclient <Server IP address>./n");
  return;
 }

 // Initialize Winsock version 2.2

 if ((Ret = WSAStartup(MAKEWORD(2,2), &wsaData)) != 0)
 {
  // NOTE: Since Winsock failed to load we cannot use WSAGetLastError
  // to determine the error code as is normally done when a Winsock
  // API fails. We have to report the return status of the function.

  printf("WSAStartup failed with error %d/n", Ret);
  return;
 }

 // Create a new socket to make a client connection.

 if ((s = socket(AF_INET, SOCK_STREAM, IPPROTO_TCP))
  == INVALID_SOCKET)
 {
  printf("socket failed with error %d/n", WSAGetLastError());
  WSACleanup();
  return;
 }

 // Setup a SOCKADDR_IN structure that will be used to connect
 // to a listening server on port 5150. For demonstration
 // purposes, we required the user to supply an IP address
 // on the command line and we filled this field in with the
 // data from the user.

 ServerAddr.sin_family = AF_INET;
 ServerAddr.sin_port = htons(Port);   
 ServerAddr.sin_addr.s_addr = inet_addr(argv[1]);

 // Make a connection to the server with socket s.

 printf("We are trying to connect to %s:%d.../n",
  inet_ntoa(ServerAddr.sin_addr), htons(ServerAddr.sin_port));

 if (connect(s, (SOCKADDR *) &ServerAddr, sizeof(ServerAddr))
  == SOCKET_ERROR)
 {
  printf("connect failed with error %d/n", WSAGetLastError());
  closesocket(s);
  WSACleanup();
  return;
 }

 printf("Our connection succeeded./n");

 // At this point you can start sending or receiving data on
 // the socket s. We will just send a hello message to the server.

 printf("We will now try to send a hello message./n");

 for(int i = 0; i<3; i++)
 {
  cin>>Data;
  if ((Ret = send(s, Data.c_str()/*"Hello"*/, Data.size(), 0)) == SOCKET_ERROR)
  {
   printf("send failed with error %d/n", WSAGetLastError());
   closesocket(s);
   WSACleanup();
   return;
  }
  printf("We successfully sent %d byte(s)./n", Ret);
 }

 // When you are finished sending and receiving data on socket s,
 // you should close the socket.

 printf("We are closing the connection./n");

 closesocket(s);

 // When your application is finished handling the connection, call
 // WSACleanup.

 WSACleanup();
 cin>>pause;
}