TCP UDP超时代码段demo

UDP的recvfrom超时：

fd_set ReadSet;

FD_ZERO(&ReadSet);

 FD_SET(sockEncoder,&ReadSet);

 timeout.tv_sec = 1;

 timeout.tv_usec = 0;

 ret = select(0, &ReadSet, NULL, NULL, &timeout);

 if(ret>0)

 {

  ret = recv(sockEncoder, buf, sizeof(buf), 0);

  if(0 > ret)

 {

   cout<<"SendToEncoder() "<<"System Error: recv from encoder"<<", error-"<<GetLastError()<<endl;

   closesocket(sockEncoder);

   return FALSE;

  }

  if(0 == ret)

 {

   cout<<"SendToEncoder() "<<"recv from encoder"<<" timeout"<<endl;

   return FALSE;

  }

 

 

TCP connect 超时：

//使不阻塞在connect

 unsigned long ul = 1;

 ioctlsocket(sockEncoder, FIONBIO, &ul);  //设置为非阻塞模式

 bool suc = false;

 timeval tm;

 fd_set set;

 char error;

 int len = sizeof(char);

 if(connect(sockEncoder, (sockaddr*)&encoderAddr, sizeof(sockaddr)) == -1)

 {

  tm.tv_sec  = 3;

  tm.tv_usec = 0;

  FD_ZERO(&set);

  FD_SET(sockEncoder, &set);

  if( select(sockEncoder+1, NULL, &set, NULL, &tm) > 0)//是否可写

  {

   getsockopt(sockEncoder,SOL_SOCKET,SO_ERROR,&error,&len);

   if(error == 0)

    suc = true;//correct IP

   else

    suc = false;

  }

  else

   suc = false;//wrong IP after time_out

 }

 else

  suc = true;

 ul = 0;

 ioctlsocket(sockEncoder, FIONBIO, &ul);  //设置为阻塞模式

 if(!suc)

 {

  closesocket( sockEncoder );

  return FALSE;

 }

 //下面进行发包收包操作