[Lazarus] lNet and several threads

User usuarioanonimomysql at gmail.com
Sat Apr 18 11:12:05 CEST 2009


Which is the simplest method?

2009/4/18 AleŇ° Katona <almindor at gmail.com>

> On Sat, 18 Apr 2009 10:36:04 +0200
> User <usuarioanonimomysql at gmail.com> wrote:
>
> > Hello, I will explain better my doubt. I need to program a multithread
> > server that processes requests of several clients at the same time. At
> the
> > moment the server processes requests of several clients one to one by the
> > OnReceive callback:
> >
> > procedure TConnectionHandler.Receive(aSocket: TLSocket);
> > var
> >   Message: String;
> > begin
> >   if aSocket.GetMessage(Message) > 0 then
> >     MessagesManager.ProcessMessage(Message);
> > end;
> >
> > I want to change the behavior of the server so that it works with one
> thread
> > for each client request.
> >
> > Is it possible?
> >
> > Best regards.
> >
> > 2009/4/18 AleŇ° Katona <almindor at gmail.com>
> >
> > > On Thu, 16 Apr 2009 20:01:57 +0200
> > > User <usuarioanonimomysql at gmail.com> wrote:
> > >
> > > > How I can use several threads with lNet visual library?
> > > >
> > > > I need some examples.
> > > >
> > > > Best regards!
> > >
> > > Hello. lNet is inheritedly not thread-safe but it can be used with
> threads
> > > in some ways. When it comes to the visual components, you must remember
> that
> > > the main program loop (handled by the widgetsets) calls the lNet
> callbacks
> > > (OnReceive etc.) so they are all executed inside the main thread no
> matter
> > > where you work with the components otherwise.
> > >
> > > I'd need some specific use case to give more info.
> > >
> > > Ales
> > > _______________________________________________
> > > Lazarus mailing list
> > > Lazarus at lazarus.freepascal.org
> > > http://www.lazarus.freepascal.org/mailman/listinfo/lazarus
> > >
>
> Yes, but you need to do the sends inside the main loop. lNet is a
> state-machine so everything related to network states needs to be kept in
> the same thread. You can however start a new thread for each request and
> process the data there. When you have replies ready to send, push them in
> some send-buffer (per client) so that the main thread can do the sending
> then. This requires some sort of messaging between the threads of course.
>
> It's not the simplest of methods but it's safe. Doing sending inside the
> work-threads could cause lNet to run into a state-change race-condition and
> stop working properly.
>
> Ales
>
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