Namedpipe

[charian0920]

Hi ... I'm using namedpipe for my interprocess communication. For each client that requires communication will have a separate instance of the namedpipe. My question is: is there an API that I could use to get the number of active instances of a namedpipe? I need this so that when my process ends it will wait first for the nedpipe server to disconnect before exiting my process. Thanks in advance ... :)

[Mark Salsbery]

Maybe GetNamedPipeHandleState() using the lpCurInstances parameter. Mark

"Posting a VB.NET question in the C++ forum will end in tears." Chris Maunder

[charian0920]

hi mark, thanks for the suggestion. however, i tried searching it in the net and couldn't find any sample implementation that uses the GetNamedPipeHandleState API. I also tried coding like this: DWORD dwCurIntances; DWORD dwState; dwCurIntances = 0; dwState = 0; while ( TRUE ) { // Wait for all the namedpipe instances to close first if( !GetNamedPipeHandleState( (HANDLE) hClientReqPipe, &dwState, &dwCurIntances, NULL, NULL, NULL, 0 ) ) { dwResult = GetLastError(); strLog.Format( "@@@@@@@@@@@@@@@@@@@@ GetNamedPipeHandleState Error: %d.", dwResult ); fnAddToMessageLog( 0, strLog ); break; } if ( dwCurIntances == 0 ) { strLog.Format( "@@@@@@@@@@@@@@@@@@@@ All namedpipe instances have been closed." ); fnAddToMessageLog( 0, strLog ); break; } } but I think it does not go the way I expected it. I'm expecting that the value of dwCurIntances during the startup is "1", since I have created the namedpipe once only. the value I get is "7". would appreciate your help. thank you. :)

[Mark Salsbery]

Hmm I'm not sure how you're getting 7. I tried your code after a single CreateNamedPipe() call and got 1, as expected. The instance count should remain equal to the number of CreateNamedPipe() calls you've made for a given name until you've closed the handle to the pipe instance. This may not be useful to you. What do you need to wait for before exiting your process ? Are you waiting for all clients to disconnect? Mark

"Go that way, really fast. If something gets in your way, turn."

[charian0920]

I need to wait for all the namedpipe instance to be disconnected by the server first before my process exit. I tried again the code, I already getting "1" for the instance count. If the server already called the DisconnectNamedPipe(), shouldn't be the number of instance decreased? thanks again :) -- modified at 10:09 Tuesday 26th June, 2007