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date: Thu, 1 Mar 2007 13:27:26 +0100,
group: microsoft.public.platformsdk.networking
back
Sockets: recv=-1 BUT WSAGetLastError=0 (??)
Hi everyone!
Something weird is happening with an application of mine:
It works OK on any computer but on one (I have nearly one hundred
installations made, up and running).
The computer on which it is not running is: WinXP professional 2002 SP2 on
AMD Athlon64
Mainly my app is a TCP server.
Each client has a listening thread with a loop and a call to the platform
SDK Windows sockets blocking (synchronous) "recv" function
(http://msdn2.microsoft.com/en-us/library/ms740121.aspx) -code below.
According to MS documentation when function "recv" returns SOCKET_ERROR
(-1), an error can be therefore retrieved with WSAGetLastError.
As you can see, I check WSAGetLastError immediately after returning recv.
This works perfectly in every computer.
But on this very one computer out of 100, several times a day, "recv"
returns SOCKET_ERROR (-1), BUT WSAGetLastError returns 0 (!!!)
Sniffing the TCP traffic via Ethereal software I can see that, in fact, the
TCP connection is still up: so it is the "recv" function that is telling me
a lie.
Has this happened to anyone out there?
Have you find any Windows or Athlon64 known bug regarding this matter
(recv=-1 but WSAGetLastError=0)?
Can you think of a way to make my application work on this problematic
computer?
Thank you very much!
Ricardo Vzquez.
Madrid, Spain.
--------------- CODE ---------------
int CClientThread::Run()
{
char msg[maxLen];
while (!bExit) {
int nRet = recv(clientSocket, msg, maxLen, 0);
if (nRet == SOCKET_ERROR && bExit) {
// Stop closes clientSocket on exit. WSAETIMEDOUT
err.Format("Stop closes clientSocket on exit");
g_logSystem.logWarning(0, err);
break;
}
else if (nRet == SOCKET_ERROR)
{
int nErr = WSAGetLastError();
if (nErr == 0)
{
err.Format("recv=-1 but WSAGetLastError=0 from client %s on socket
%ld.", clientId, clientSocket);
g_logSystem.logWarning(0, err);
continue;
}
else
{
err.Format("Connection lost with client %s on socket %ld. Error code
%ld: recv() = SOCKET_ERROR", clientId, clientSocket, nErr);
g_logSystem.logWarning(0, err);
closesocket(clientSocket);
server->DeleteClient(clientSocket);
cti_RemoveEventListener(this);
return SOCKET_ERROR;
}
}
else if (!nRet) {
// Connection has been gracefully closed.
err.Format("Client %s with socket %ld has closed the connection: recv() =
0 (apparently)", clientId, clientSocket);
g_logSystem.logNormal(0, err);
closesocket(clientSocket);
server->DeleteClient(clientSocket);
cti_RemoveEventListener(this);
return 0;
}
else {
// Proccess message:
msg[nRet] = 0x0;
err.Format("[Cli %ld] Received: %s", clientSocket, msg);
g_logSystem.logNormal(4, err);
CString sMensaje;
sMensaje = CStrTok(msg, "%");
while (!sMensaje.IsEmpty())
{
parse(sMensaje);
sMensaje = CStrTok("", "%");
}
}
}
return 0;
}
date: Thu, 1 Mar 2007 13:27:26 +0100
author: Ricardo Vazquez
Re: Sockets: recv=-1 BUT WSAGetLastError=0 (??)
Since there's been no response in any of the groups you selected, you might
try asking this question in alt.winsock.programming
"Ricardo Vazquez" wrote in message
news:%23NZWMz$WHHA.528@TK2MSFTNGP03.phx.gbl...
> Hi everyone!
>
> Something weird is happening with an application of mine:
> It works OK on any computer but on one (I have nearly one hundred
> installations made, up and running).
> The computer on which it is not running is: WinXP professional 2002 SP2 on
> AMD Athlon64
>
> Mainly my app is a TCP server.
> Each client has a listening thread with a loop and a call to the platform
> SDK Windows sockets blocking (synchronous) "recv" function
> (http://msdn2.microsoft.com/en-us/library/ms740121.aspx) -code below.
>
> According to MS documentation when function "recv" returns SOCKET_ERROR
> (-1), an error can be therefore retrieved with WSAGetLastError.
> As you can see, I check WSAGetLastError immediately after returning recv.
> This works perfectly in every computer.
> But on this very one computer out of 100, several times a day, "recv"
> returns SOCKET_ERROR (-1), BUT WSAGetLastError returns 0 (!!!)
> Sniffing the TCP traffic via Ethereal software I can see that, in fact,
the
> TCP connection is still up: so it is the "recv" function that is telling
me
> a lie.
>
> Has this happened to anyone out there?
> Have you find any Windows or Athlon64 known bug regarding this matter
> (recv=-1 but WSAGetLastError=0)?
> Can you think of a way to make my application work on this problematic
> computer?
>
> Thank you very much!
>
> Ricardo Vzquez.
> Madrid, Spain.
>
>
> --------------- CODE ---------------
> int CClientThread::Run()
> {
> char msg[maxLen];
>
> while (!bExit) {
> int nRet = recv(clientSocket, msg, maxLen, 0);
> if (nRet == SOCKET_ERROR && bExit) {
> // Stop closes clientSocket on exit. WSAETIMEDOUT
> err.Format("Stop closes clientSocket on exit");
> g_logSystem.logWarning(0, err);
> break;
> }
> else if (nRet == SOCKET_ERROR)
> {
> int nErr = WSAGetLastError();
> if (nErr == 0)
> {
> err.Format("recv=-1 but WSAGetLastError=0 from client %s on socket
> %ld.", clientId, clientSocket);
> g_logSystem.logWarning(0, err);
> continue;
> }
> else
> {
> err.Format("Connection lost with client %s on socket %ld. Error code
> %ld: recv() = SOCKET_ERROR", clientId, clientSocket, nErr);
> g_logSystem.logWarning(0, err);
>
> closesocket(clientSocket);
> server->DeleteClient(clientSocket);
> cti_RemoveEventListener(this);
> return SOCKET_ERROR;
> }
> }
> else if (!nRet) {
> // Connection has been gracefully closed.
> err.Format("Client %s with socket %ld has closed the connection: recv()
=
> 0 (apparently)", clientId, clientSocket);
> g_logSystem.logNormal(0, err);
>
> closesocket(clientSocket);
> server->DeleteClient(clientSocket);
> cti_RemoveEventListener(this);
> return 0;
> }
> else {
> // Proccess message:
> msg[nRet] = 0x0;
> err.Format("[Cli %ld] Received: %s", clientSocket, msg);
> g_logSystem.logNormal(4, err);
>
> CString sMensaje;
> sMensaje = CStrTok(msg, "%");
> while (!sMensaje.IsEmpty())
> {
> parse(sMensaje);
> sMensaje = CStrTok("", "%");
> }
> }
> }
> return 0;
> }
>
>
>
date: Fri, 2 Mar 2007 09:31:02 -0800
author: Michael K. O'Neill
Re: Sockets: recv=-1 BUT WSAGetLastError=0 (??)
Are you sure you call GetLastError() exactly after you check return code of
recv() ? Just a hint
Arkady
"Ricardo Vazquez" wrote in message
news:%23NZWMz$WHHA.528@TK2MSFTNGP03.phx.gbl...
> Hi everyone!
>
> Something weird is happening with an application of mine:
> It works OK on any computer but on one (I have nearly one hundred
> installations made, up and running).
> The computer on which it is not running is: WinXP professional 2002 SP2 on
> AMD Athlon64
>
> Mainly my app is a TCP server.
> Each client has a listening thread with a loop and a call to the platform
> SDK Windows sockets blocking (synchronous) "recv" function
> (http://msdn2.microsoft.com/en-us/library/ms740121.aspx) -code below.
>
> According to MS documentation when function "recv" returns SOCKET_ERROR
> (-1), an error can be therefore retrieved with WSAGetLastError.
> As you can see, I check WSAGetLastError immediately after returning recv.
> This works perfectly in every computer.
> But on this very one computer out of 100, several times a day, "recv"
> returns SOCKET_ERROR (-1), BUT WSAGetLastError returns 0 (!!!)
> Sniffing the TCP traffic via Ethereal software I can see that, in fact,
> the TCP connection is still up: so it is the "recv" function that is
> telling me a lie.
>
> Has this happened to anyone out there?
> Have you find any Windows or Athlon64 known bug regarding this matter
> (recv=-1 but WSAGetLastError=0)?
> Can you think of a way to make my application work on this problematic
> computer?
>
> Thank you very much!
>
> Ricardo Vzquez.
> Madrid, Spain.
>
>
> --------------- CODE ---------------
> int CClientThread::Run()
> {
> char msg[maxLen];
>
> while (!bExit) {
> int nRet = recv(clientSocket, msg, maxLen, 0);
> if (nRet == SOCKET_ERROR && bExit) {
> // Stop closes clientSocket on exit. WSAETIMEDOUT
> err.Format("Stop closes clientSocket on exit");
> g_logSystem.logWarning(0, err);
> break;
> }
> else if (nRet == SOCKET_ERROR)
> {
> int nErr = WSAGetLastError();
> if (nErr == 0)
> {
> err.Format("recv=-1 but WSAGetLastError=0 from client %s on socket
> %ld.", clientId, clientSocket);
> g_logSystem.logWarning(0, err);
> continue;
> }
> else
> {
> err.Format("Connection lost with client %s on socket %ld. Error code
> %ld: recv() = SOCKET_ERROR", clientId, clientSocket, nErr);
> g_logSystem.logWarning(0, err);
>
> closesocket(clientSocket);
> server->DeleteClient(clientSocket);
> cti_RemoveEventListener(this);
> return SOCKET_ERROR;
> }
> }
> else if (!nRet) {
> // Connection has been gracefully closed.
> err.Format("Client %s with socket %ld has closed the connection: recv()
> = 0 (apparently)", clientId, clientSocket);
> g_logSystem.logNormal(0, err);
>
> closesocket(clientSocket);
> server->DeleteClient(clientSocket);
> cti_RemoveEventListener(this);
> return 0;
> }
> else {
> // Proccess message:
> msg[nRet] = 0x0;
> err.Format("[Cli %ld] Received: %s", clientSocket, msg);
> g_logSystem.logNormal(4, err);
>
> CString sMensaje;
> sMensaje = CStrTok(msg, "%");
> while (!sMensaje.IsEmpty())
> {
> parse(sMensaje);
> sMensaje = CStrTok("", "%");
> }
> }
> }
> return 0;
> }
>
>
>
date: Mon, 5 Mar 2007 09:26:37 +0200
author: Arkady Frenkel
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