Re: proper way to close a socket?
Hector,
I tried to study and understand your code. Am I right that you are basically
polling the socket until it either connects or the connection attempt times
out?
Is there an advantage to this over waiting for the OnConnect call to come
with either no error meaning conencted or an error meaning timeout?
Will the OnConnect call always always always come in?
It seems a shame that there is no way to abort a connection attempt until it
gives up and gives the timeout. I'm wondering where does the timeout call
come from? If I'm trying to connect to an IP address that doesn't exist,
then I'm guessing that it's the socket code in Windows of my own PC that is
giving me the timeout. If that's the case, I'm surprised that it can't
coordinate that with a deleted object or one where Close was already called.
I suppose I could do one more thing. If the user presses the button to close
the connection before it's connected, I can leave that socket undeleted to
wait for the OnConnect and then delete itself inside the OnConnect call. If
the user presses the button again to make a new connection, I can create a
new socket to handle that request, even if the abandoned one is still not
shut down.
Thanks,
Bill
"Hector Santos" <sant9442@nospam.gmail.com> wrote in message
news:O2M8cWlxKHA.5940@TK2MSFTNGP02.phx.gbl...
When I added the yield, I threw out the nCountDown timeout calculation.
Change it to this:
BOOL CMyClientSocket::WaitConnect(int nTimeout)
{
int nSleep = 100;
DWORD tFinal = GetTickCount()+nTimeout*1000;
for (;;) {
if (GetTickCount() > tFinal) {
SetLastError(WSAETIMEDOUT);
return FALSE;
}
....
}
---
Hector Santos wrote:
Ok, Bill,
What you need to do is do wait on the Connect() like so:
if(!m_pClientSocket->Connect(m_toURL, m_toPort)) {
int err = GetLastError();
if (err == WSAEWOULDBLOCK) {
if (!m_pClientSocket->WaitConnect(5)) {
// WaitConnect Error, Show Error
err = GetLastError();
m_pClientSocket->Close();
return;
}
} else {
// Connect Error, Show Error
err = GetLastError();
m_pClientSocket->Close();
return;
}
}
The WaitConnect() and AsyncYield() functions are a member of your socket
subclass
BOOL CMyClientSocket::WaitConnect(int nTimeout)
{
int nSleep = 100;
int nCountDown = nTimeout*1000 / nSleep;
DWORD t1 = GetTickCount();
for (;;) {
nCountDown--;
if (nCountDown <= 0) {
SetLastError(WSAETIMEDOUT);
return FALSE;
}
fd_set efds; fd_set wfds;
FD_ZERO(&efds); FD_ZERO(&wfds);
FD_SET(m_hSocket, &efds);
FD_SET(m_hSocket, &wfds);
struct timeval tv;
tv.tv_sec = 0;
tv.tv_usec = nSleep*1000;
int rc = select(0, NULL, &wfds, &efds, &tv);
switch (rc) {
case 0:
// WE TIMED OUT!!
{
/* show timeout in some CListBox
CString s;
s.Format("- wait %d | %d",nCountDown, GetTickCount()-t1);
m_dlg->m_log.InsertString(0,s);
*/
if (AsyncYield(100)) {
SetLastError(WSAECONNABORTED);
return FALSE;
}
}
break;
case SOCKET_ERROR:
if (GetLastError() != WSAEWOULDBLOCK) return FALSE;
break;
default:
if (FD_ISSET(m_hSocket,&wfds)) {
// WE CONNECTED!!
SetLastError(0);
return TRUE;
}
if (FD_ISSET(m_hSocket,&efds)) {
// WE FAILED
SetLastError(WSAEHOSTUNREACH);
return FALSE;
}
break;
}
}
return FALSE;
}
BOOL CMyClientSocket::AsyncYield(DWORD nDelay)
{
DWORD nDone = (GetTickCount() + nDelay);
while (nDone > GetTickCount()){
Sleep(75);
MSG msg;
while (::PeekMessage(&msg,NULL,0,0,PM_REMOVE)){
::TranslateMessage(&msg);
::DispatchMessage(&msg);
}
if (m_cancel) {
m_cancel = FALSE;
return TRUE;
}
}
return FALSE;
}
My previous message had more details about using the select() socket
function. The wait block will use select() which allows you to detect
read, write and error events. In this case, you need two events:
write event - signals the connection is ready
error event - something went wrong
That will do the trick for you.
--
HLS