Re: How to handle abnormal user disconnection condition from server?

From:

"Scott McPhillips [MVP]" <org-dot-mvps-at-scottmcp>

Newsgroups:

microsoft.public.vc.mfc

Date:

Thu, 25 Sep 2008 22:33:20 -0400

Message-ID:

<O$Gf#A4HJHA.944@TK2MSFTNGP03.phx.gbl>

"Landon" <Landon@discussions.microsoft.com> wrote in message
news:0ED02E26-F282-4AE6-BE6C-E2F9C110CA25@microsoft.com...

I use MFC Visual C++ 4.2.

I developed a simple network application to send message inter-clients and
the number of clients also only a few persons ( about less than 10
persons ).

I have succeeded in establishing server-client and client-server
connection,
sending and receiving messages from client.

Now my problem are:
1. I need to send a message from a client to other client. How to know
that
the message I sent will be received by the correct user intended, not
missed
to other user?

You could add an acknowledge message to your protocol. Receiving the
acknowledge tells you that the message was received.

2. How to handle the condition of unexpected user disconnection from
server?
E.g. : the user workstation hung and need to be restarted so it does not
have
the chance to send message notifying the server if it was going to
disconnect.
or the user workstation experiencing malfunction and suddenly shutted
down.

3. I plan to use a CObList or pointer object to handle all the clients
connections. If the problem no. 2 occurs, then that client's pointer will
be
left unmaintained on the server and it will cause memory leak because the
object has not been released from the memory.
How to handle this condition?

Thank you very much.

You could add a periodic "I am alive" message from all clients to the
server. The server can use a timer to detect loss of connection. When you
detect that a client has died you can destroy its socket.

--
Scott McPhillips [VC++ MVP]