阻塞式TCP 接收方式

// robust version of receiving data
int _recv(int sp, char *buffer,int len,int flag)
{
if( sp < 0 || NULL==buffer )
{
DBG_MSG("_recv if( sp < 0 || NULL==buffer )");
return -1;
}


timeval timeout;
timeout.tv_sec = 5;   //wait seconds
timeout.tv_usec = 0;
fd_set  fdmask;


new_select:


FD_ZERO(&fdmask);// clear
FD_SET((unsigned int) sp, &fdmask);// add
int rc = select( sp+1, &fdmask, NULL, NULL, &timeout);
if (rc <= 0)
{
DWORD err = WSAGetLastError();


DBG_MSG("Surveon|trace select socket=[%d] err \n",sp);
Flog("Trace _rect select socket=[%d] err:%u\n",sp,err);
if (rc ==0)
{
return rc;
}


return SOCKET_ERROR; //-1=error
}


if(! FD_ISSET(sp,&fdmask))
goto new_select;


rc = recv(sp,buffer,len,flag);
return rc;
}