带超时的recv函数

周末了，用纯C/C++写了一个服务端，简单：

 #include <winsock2.h>
#include <stdio.h>
#pragma comment(lib, "ws2_32.lib")
 
int main()
{
  WORD wVersionRequested;
  WSADATA wsaData;
  wVersionRequested = MAKEWORD(1, 1);
  
  WSAStartup( wVersionRequested, &wsaData );
 
  SOCKET sockClient = socket(AF_INET, SOCK_STREAM, 0);
 
  SOCKADDR_IN addrSrv;
  addrSrv.sin_addr.S_un.S_addr = inet_addr("127.0.0.1");
  addrSrv.sin_family = AF_INET;
  addrSrv.sin_port = htons(8888);
 
  int ret = connect(sockClient, (SOCKADDR*)&addrSrv, sizeof(SOCKADDR));
  printf("connect ret is %d\n", ret);
  
  fd_set rfds;
  struct timeval timeout = {4, 0};
 
  FD_ZERO(&rfds); 
  FD_SET(sockClient, &rfds);
  ret = select(-1, &rfds, NULL, NULL, &timeout);
  printf("select ret is %d\n",ret);
  if(0 > ret)
  {
    printf("select error\n");
    return -1;
  }
   
  if(0 == ret)
  {
    printf("time out\n");
    return -2;
  }
    
  if(FD_ISSET(sockClient, &rfds))
  {
    char recvBuf[200] = "x";
    ret = recv(sockClient, recvBuf, 100, 0);
    if(0 > ret)
    {
      printf("recv error");
      return -3;
    }
 
    if(0 == ret)
    {
      printf("recv ret is %d, buf is %s\n", ret, recvBuf);
      return -4;
    }
    
    printf("%s\n", recvBuf);
    }
 
  while(1);
  closesocket(sockClient);
  WSACleanup();
 
  return 0;
}

实现了带超时的recv函数。