Re: Need help with multi threading

[Robert Pearce <rob bdt-home demon co uk>]

Hi kiet,

On Thu, 1 Mar 2012 18:00:31 +1100 you wrote:
> 
> I'm in a situation where I need to stay in a loop to listen for data from
> the other end of socket connection, and at the same time I want to
> update/display my GUI according to the information coming in.
> 
OK

> The GUI that going to display these informations is a pop-up diaglog box.
>
OK
 
> So I  think to fix this I need to spawn a thread for the pop-up diaglog box.
> 
No, you don't. At least, that certainly isn't the ONLY solution, and in
GTK it's almost certainly not the best or easiest solution either.

The option I'd look at first is to remove the "stay in a loop" you
first mentioned. Hook up your socket to a GIO::Channel (not sure on
name, I use the unwrapped g_io_channel_... method) and then connect a
handler to that channel's event signals. That way you can process the
incoming data within the GLib/Gtk main loop. No need for threads at all.

The other option to look at is to leave your whole GUI running in the
main thread, but to launch your "loop to listen for data" into a second
thread. That thread can then buffer the data and use a GLib::Dispatcher
to trigger a main thread call-back to handle it (which I think is what
GIO::Channel does internally on some platforms). Alternatively the
socket thread could process the data and use a GLib::Dispatcher to
trigger a dialog update. There's an example of this in the GLib-mm docs
at gnome.org

> Thus could some one please point me to some websites that show me how to
> operate multi threading in gtkmm or sample code to get a simple one
> running, thank-you.
> 
www.gnome.org/docs/glibmm/group__Threads.html (or some variant of that
- I'm looking at a local copy that was installed with the package)

Rob