Re: gtk & threads

[Tom Gilbert <gilbertt tomgilbert freeserve co uk>]

* bob@cs.csoft.net (bob@cs.csoft.net) wrote:
> Is gtk thread safe?

The answer is a cross between kind-of, and yes.

Basically though, yes. Although not technically thread-safe, it is
close to being so.

The thread-safety rules basically go as follows:
o call g_thread_init() before gtk_main() or any other gtk/gdk/glib calls.
o When using gtk/gdk calls, always surround them with gdk_threads_enter()
  and gdk_threads_leave().

While this is technically not thread-safe behavior (since thread-safety
means that the gtk/gdk calls do this themselves), it is close enough in 
practice for most people. (Extra typing not withstanding ;)

See:
    http://www.gtk.org/rdp/glib/glib-threads.html
    http://www.gtk.org/rdp/gdk/gdk-threads.html

For more info. They're better at this stuff than me...

> I am trying to figure out how to get past gtk's "cant refresh while in a
> function" problem.
> Using threads, I think, would be the best way around it, but I dont see
> anything on gtk.org about thread safety.

Threads are one way around this, there are others.
Timeouts are nice for keeping the frontend up-to-date, or you could
just do something like 
if(gtk_events_pending())
   gtk_main_iteration();
(I don't have the code in front of me right now, but its real close to
this). This is clean for simple situations only though IMO.

If it suits your application, you could even separate the frontend
completely from the data engine (not necessarily by threads, you could
spawn a separate process for this, send it data, and have the results
refreshed into the display. I quite like this for some things, as you
can kill the process cold if the user cancels some action, or chooses
to do something else... I was going to implement this eventually in my
scrabble game some day...)

Tom.
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