Re: accessing widgets from different threads

[klaus triendl <klaus triendl eu>]

Christopher Harvey schrieb:
> Hi list,
> I've got a gtksourceview widget (but this post isn't about the fact that
> it's gtksourceview widget, it could be any widget) and I'd like to run
> some regular expressions on the text in the source buffer when the user
> isn't typing. I'd like the regular expressions to run in a separate
> thread to keep the application responsive. So the questions is: how can
> I get the text out of a widget when the user could be typing in it any
> any time? I know I have to serialize access to the widget but when there
> is another thread doing all of the GUI interaction I don't see how I can
> tell it to not deal with a given widget at any given moment. I only need
> to stop the GUI thread so I can get a copy of the current text buffer,
> but I'm afraid at that moment of the copy the user may hit a key and
> break something in the widget.
>
> I can't just get a copy of the source every time the user hits a key and
> changes the text because that would be too much copying. I need to wait
> a second or two after the user has stopped typing then get the copy.

I would let the gui thread handle the timeout (wait 1 second to get the 
user's input, see signal_timout), copy the text from the widget in the 
timeout handler and send it to the regular expression thread which in 
turn sends back an answer if necessary.

There is a Glib::Dispatcher which enables you to send notifications 
inbetween threads. In GLib there exists something like asynchronous 
queues or you could use a whole framework like sigx to handle the 
interthread communication.

This is a rather generic answer for the sake of brevity, I'm afraid, but 
it should give you a clue how to achieve what you want


Klaus