Re: [gtk-list] Re: XInitThreads causing problems to GTK windows.

[Sebastian Wilhelmi <wilhelmi ira uka de>]

Hi, Olaf

> > Just don't use XInitThreads(), as it will slow down things additionally
> > and gtk already takes care of that. But you have to call g_thread_init()
> > before the call to gtk_init(). And then you have to call gdk_thread_enter()
> > before any call to gtk/gdk-function and gdk_thread_leave() afterwards; not
> > within
> 
> Is that necessary even if I don't call gtk functions from anywhere
> _except_ the main thread?

No, than it isn't necessary. You have to call g_thread_init() however to make
GLib thread-safe. You can than also use the portable GLIb thread system for
things like mutexes.

> Is it possible to establish a communication link between the main thread
> and some separate 'worker thread' based on (X- ?) Events? 

Yes, but that is in general much more work than just calling
gdk_threads_enter() before the command itself and gdk_threads_leave()
afterwards.

> So, every time
> the worker thread wants to GUI to be updated somehow, it might post a
> message into the main thread's message queue (does each thread have a
> separate message queue, like in Win32? I don't think so..). 

There aren't message queue, unless you program them. They would have to be
prepared to take all actions, that a worker thread might issue. If those
actions are only a few (update a progress bar and such) it is quite easy, but
if the worker thread wants yo use much of the gtk-API it is easier the other
way.

> At some later time, the main thread reads that message and performs the
> required GUI work.
> How could this be done?

Define a struct, that can hold all the actions you would want to do and make a
GQueue hold them. Add from one thread, read from the other. As noted above. In
general don't do that.

> > signals, as they already hold the lock but also before gtk_main() and 
> friends.
> 
> A silly question: What do you mean by 'signals'? GTK signal handlers? Or
> something that has to do with Unix process signals? I'm not yet very
> familiar with unix programming, so excuse my lack of knowledge...

I of course mean GTK+signals here.
 
Tschüß
Sebastian
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