c++ socket通信

socket通信是支持域名发送的，但是不能直接用域名发送，需要先解析域名，获取到实际IP地址才可以。

int SendMsg(char *szMsg, int nMsgLen)
{
   int nRet = 0;
   if(strlen(m_szIp) <= 0)
       return -1;

   WSADATA wsaData;
   int iResult = WSAStartup(MAKEWORD(2,2), &wsaData);
   if (iResult != NO_ERROR)
       return -1;

   m_sock = socket(AF_INET, SOCK_STREAM, IPPROTO_TCP);
   if(INVALID_SOCKET == m_sock)
   {
       WSACleanup();
       return -1;
   }
   SOCKADDR_IN saddr;

   if (NULL == strstr(m_szIp, "com"))
   {
       saddr.sin_addr.S_un.S_addr = inet_addr(m_szIp);
   }
   else
   {
       struct hostent *hptr = NULL;

       if (NULL == (hptr = gethostbyname(m_szIp)))
       {
           return 1;
       }

CopyMemory(&saddr.sin_addr.S_un.S_addr, hptr->h_addr_list[0], hptr->h_length);

printf("hptr->h_addr_list[0] = %s\n", hptr->h_addr_list[0]);

}

saddr.sin_family = AF_INET;
saddr.sin_port = htons((WORD)m_port);

// set the socket in non-blocking
   unsigned long mode = 1;
   int result = ioctlsocket(m_sock, FIONBIO, &mode);
   if (result != NO_ERROR)
       printf("ioctlsocket failed with error: %ld\n", result);

     printf("connect start...");
   nRet = connect(m_sock, (const sockaddr *)&saddr, sizeof(SOCKADDR_IN));
     printf("connect finish...");

   // restart the socket mode
   mode = 0;
   result = ioctlsocket(m_sock, FIONBIO, &mode);
   if (result != NO_ERROR)
         printf("ioctlsocket failed with error: %ld\n", result);

   fd_set Write;
   FD_ZERO(&Write);
   FD_SET(m_sock, &Write);

   // check if the socket is ready
   TIMEVAL timeval = {0};
   timeval.tv_sec = 3;
   timeval.tv_usec = 0;

     printf("select start...");
   int selectresult = select(0, NULL, &Write, NULL, &timeval);
     printf("select finish.");

   switch (selectresult)
   {
   case -1:
       return R_FAILURE;
   case 0 : //超时
       return R_FAILURE;
   default: //读就绪
       break;
   }

   if(!FD_ISSET(m_sock, &Write))
   {
         printf("FD_ISSET error.");
       return S_FALSE;
   }

printf("send start...");

setsockopt(m_sock, SOL_SOCKET, SO_SNDTIMEO, (const char*)&timeval, sizeof(timeval));

nRet = send(m_sock, szMsg, nMsgLen, 0);

printf("send finish.");

return S_OK;
}

int RecvMsg(std::string &srecv, int timeout/*=3*/)
{
   struct timeval Timeout;
   fd_set   rfds;
   int   nfds, selectresult;
   char buff[4097] = {0};
   int buffLen = 4096;
   int rest = buffLen, done = 0, recvbytes;

   int nlen = 0;
   //设置超时时间
   Timeout.tv_sec = timeout;
   Timeout.tv_usec = 0;

#ifndef _MSC_VER
nfds = getdtablesize();
#else
nfds = 0;
#endif

FD_ZERO(&rfds);
FD_SET(m_sock, &rfds);

   if(timeout < 0)
       selectresult = select(nfds, &rfds, (fd_set*)0, (fd_set*)0, NULL);
   else
       selectresult = select(nfds, &rfds, (fd_set*)0, (fd_set*)0, &Timeout);

   switch (selectresult)
   {
   case -1:
       return R_FAILURE;
   case 0 : //超时
       return R_FAILURE;
   default: //读就绪
       break;
   }
   while(recvbytes = recv(m_sock, buff, rest, 0))
   {
       if(recvbytes == -1)
       {
           return R_FAILURE;
       }
       if(recvbytes < 0)
       {
           //接收异常
           return R_FAILURE;
       }

       if(recvbytes ==0)
       {
           //连接被对端关闭
           return (recvbytes);
       }

       srecv +=buff;
       done += recvbytes;
       memset(buff,0,4097);
       if(recvbytes == 4096)
       {
           continue;
       }
       //select again
       Timeout.tv_sec = 0;
       Timeout.tv_usec = 500000; /* 0.5 sec */
       if(timeout < 0)
           selectresult = select(nfds, &rfds, (fd_set*)0, (fd_set*)0, NULL);
       else
           selectresult = select(nfds, &rfds, (fd_set*)0, (fd_set*)0, &Timeout);

switch (selectresult)
{

       case -1:
           return done;
       case 0 : //超时
           return done;
       default: //读就绪
           break;
       }
   }
   return (done + recvbytes);
}

猜你喜欢