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asynchronous socket operations - question

I have a question about C#. How can I stop asynchronous read/write operation
( BeginReceive() / BeginSend() ) if timeout occurs?
The Socket class doesn't make any cancel method available.
I used CancelIo(HANDLE hFile) method (declared in Winbase.h) in C++.

Thanks for help.
Olek
Nov 15 '05 #1
5 5648
You could always spawn a new thread which then calls the synchronous
version, into which you can place a timeout parameter.

"a.kostrzew a" <aX.kostrzewaX@ remove_this_and _X.uposX.comX.p lX> wrote in
message news:bm******** **@nemesis.news .tpi.pl...
I have a question about C#. How can I stop asynchronous read/write operation
( BeginReceive() / BeginSend() ) if timeout occurs?
The Socket class doesn't make any cancel method available.
I used CancelIo(HANDLE hFile) method (declared in Winbase.h) in C++.

Thanks for help.
Olek

Nov 15 '05 #2
I might be wrong here.. but, can you call EndSend() to complete the
operation?

--
Girish Bharadwaj
"Daniel Bass" <I'm really @ sick of spam> wrote in message
news:O8******** ******@TK2MSFTN GP10.phx.gbl...
You could always spawn a new thread which then calls the synchronous
version, into which you can place a timeout parameter.

"a.kostrzew a" <aX.kostrzewaX@ remove_this_and _X.uposX.comX.p lX> wrote in
message news:bm******** **@nemesis.news .tpi.pl...
I have a question about C#. How can I stop asynchronous read/write operation ( BeginReceive() / BeginSend() ) if timeout occurs?
The Socket class doesn't make any cancel method available.
I used CancelIo(HANDLE hFile) method (declared in Winbase.h) in C++.

Thanks for help.
Olek

Nov 15 '05 #3
Yes, of course.
I call asynchronous read operation in this way:

IAsyncResult oResult = oSocket.BeginRe ceive(...);
oWH = m_oResult .AsyncWaitHandl e;
// oEventsHandler - my class object
oEventsHandler. WaitForGroupEQ( Timeout.Infinit e ,nGroupId,out nEvent);
int nNumberOfBytesR ead = ReadEnd();

But I can't break this operation.

Best regards,
Olek

U¿ytkownik "Girish Bharadwaj" <girishb.at.mvp s.dot.org> napisa³ w wiadomo¶ci
news:OM******** ******@TK2MSFTN GP09.phx.gbl...
I might be wrong here.. but, can you call EndSend() to complete the
operation?

--
Girish Bharadwaj
"Daniel Bass" <I'm really @ sick of spam> wrote in message
news:O8******** ******@TK2MSFTN GP10.phx.gbl...
You could always spawn a new thread which then calls the synchronous
version, into which you can place a timeout parameter.

"a.kostrzew a" <aX.kostrzewaX@ remove_this_and _X.uposX.comX.p lX> wrote in
message news:bm******** **@nemesis.news .tpi.pl...
I have a question about C#. How can I stop asynchronous read/write

operation
( BeginReceive() / BeginSend() ) if timeout occurs?
The Socket class doesn't make any cancel method available.
I used CancelIo(HANDLE hFile) method (declared in Winbase.h) in C++.

Thanks for help.
Olek


Nov 15 '05 #4
"a.kostrzew a" <aX.kostrzewaX@ remove_this_and _X.uposX.comX.p lX> wrote in message news:<bm******* ***@atlantis.ne ws.tpi.pl>...
Yes, of course.
I call asynchronous read operation in this way:

IAsyncResult oResult = oSocket.BeginRe ceive(...);
oWH = m_oResult .AsyncWaitHandl e;
// oEventsHandler - my class object
oEventsHandler. WaitForGroupEQ( Timeout.Infinit e ,nGroupId,out nEvent);
int nNumberOfBytesR ead = ReadEnd();

But I can't break this operation.

Olek -

From what I can tell from your code it looks like you are blocking
the main thread until the EndReceive() callback method fires. This
somewhat defeats the purpose of using an asynchronous socket call.
Instead of waiting indefinitely for an answer, why don't you put a
reasonable timeout time in the WaitForGroupEQ method. When the timeout
is reached you know there wasn't a response. If you then Close() the
Socket object, the EndReceive() method will fire, and throw an
Exception. You should catch the Exception in a try-catch block and
handle it accordingly.

Alternatively, you can use the blocking Receive() method, and set
the ReceiveTimeout Socket option property to a reasonable value. The
Receive() method will throw an Exception if the timeout is reached
before data is received. Hope this helps solve your problem.

Rich Blum - Author
"C# Network Programming" (Sybex)
http://www.sybex.com/sybexbooks.nsf/Booklist/4176
"Network Performance Open Source Toolkit" (Wiley)
http://www.wiley.com/WileyCDA/WileyT...471433012.html
Nov 15 '05 #5
I'm grateful for help.
But in Yours solution I can't send any message after timeout on receive
(socket is closed!).
This way I would like to avoid Close() method.
Unfortunely I can't use alternatively method - blocking Receive().

Olek

Uzytkownik "Rich Blum" <ri*******@juno .com> napisal w wiadomosci
news:cc******** *************** ***@posting.goo gle.com...
"a.kostrzew a" <aX.kostrzewaX@ remove_this_and _X.uposX.comX.p lX> wrote in

message news:<bm******* ***@atlantis.ne ws.tpi.pl>...
Yes, of course.
I call asynchronous read operation in this way:

IAsyncResult oResult = oSocket.BeginRe ceive(...);
oWH = m_oResult .AsyncWaitHandl e;
// oEventsHandler - my class object
oEventsHandler. WaitForGroupEQ( Timeout.Infinit e ,nGroupId,out nEvent);
int nNumberOfBytesR ead = ReadEnd();

But I can't break this operation.

Olek -

From what I can tell from your code it looks like you are blocking
the main thread until the EndReceive() callback method fires. This
somewhat defeats the purpose of using an asynchronous socket call.
Instead of waiting indefinitely for an answer, why don't you put a
reasonable timeout time in the WaitForGroupEQ method. When the timeout
is reached you know there wasn't a response. If you then Close() the
Socket object, the EndReceive() method will fire, and throw an
Exception. You should catch the Exception in a try-catch block and
handle it accordingly.

Alternatively, you can use the blocking Receive() method, and set
the ReceiveTimeout Socket option property to a reasonable value. The
Receive() method will throw an Exception if the timeout is reached
before data is received. Hope this helps solve your problem.

Rich Blum - Author
"C# Network Programming" (Sybex)
http://www.sybex.com/sybexbooks.nsf/Booklist/4176
"Network Performance Open Source Toolkit" (Wiley)
http://www.wiley.com/WileyCDA/WileyT...471433012.html

Nov 15 '05 #6

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