Re: Winsock / Sockets programming

"Mark Salsbery [MVP]" <MarkSalsbery[MVP]@newsgroup.nospam>
Tue, 8 Jul 2008 10:38:07 -0700
"Peter" <> wrote in message

Working with Winsock

I am making this post because I need help with Winsock Programming.

About the application: I want to create a client/server application.
At the client side receive message from the server only, send message
to the server only. In the Server side receive message from all the
clients, broadcast message, and send message to individual clients.

So far, I have read some information about Winsock, and I have managed
to create in a dialog application the win console application example

But I am having problem when I want to create different sockets so
allocate it to more than one machine.

The 2 problem I am facing now is I am not sure if I should create one
socket on one port. And connect everybody to that socket like a big
chat room and do the sorting/find at the CString buffer, the problem I
see is that all the end user will need to be looking for their message
in a big CString buffer.

The second approach will be create socket to each client (at this
point I am not sure if you can create more than one socket attached to
the same port, remember I want to sent message to a unique client at a
time. In my try application if I don?t disconnect/destroyed the socket
and create it again when I receive a message from the server I receive
it twice, telling me I can have more that one socket to attached at
the same port, but I am not sure if I can send it to a particular
socket or it just broad cast because it is attached to the same port.)
I could allocate a port and a socket to each client so every one has
his own socket and port attached, but this approach could ending me up
with a server that need to be looking for 200+ ports

Let discuss this problem only here because the second problem depend
on what approach I go ahead.

Unless you have some specific needs, the only socket port you need to worry
about is the listener socket.

When the server (listener) accepts a connection, a new socket is created
which is connected to the client. You don't need to worry what port that's

The client-end socket doesn't need to be bound to a particular port - the
system will assign one by default. The client socket only needs to know the
server's listener port to make the connection.

Two sockets may share a port if their protocols are different, but you
cannot have, for example, two TCP sockets on the same port at the same


Mark Salsbery
Microsoft MVP - Visual C++

Thank you for your help,


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