Re: [gtkmm] Dispatcher/ Threading

[Christer Palm <palm nogui se>]

Glenn Pierce wrote:
> I have read the doxygen docs and the dispatcher example but I couldn't
> find an overview of the threading problem and when / why dispatcher
> needs to be used.

Did you also check the FAQ? There's a (rather brief) article about 
threads there 
(http://www.gtkmm.org/docs/gtkmm-2.4/docs/FAQ/html/index.html#id2502297).

Gtkmm isn't thread safe, which means that if you manipulate gtkmm 
objects from several threads at the same time your application will 
crash and burn. This is not unique to GTK+/gtkmm - pretty much all GUI 
toolkits have the same characteristics.

To use threads in a GTK+/gtkmm application you have two choices.

1) Do your own locking using gdk_threads_enter() and gdk_threads_leave() 
to make sure that only one thread can manipulate the GUI at the same time.

2) Only make GTK+/gtkmm calls from one thread. If another thread wants 
to update the GUI it'll need to ask the "GUI"-thread to do it, which is 
what you'd use a Glib::Dispatcher for.

IMHO, choice 2 is the preferred choice.

--
Christer Palm