Friday, May 23, 2008

Syx, GTK+ and threading

you all know that Gtk+ has locks for the GUI when dealing with the X server and prevent async events to be sent. This is done by manually acquiring/releasing the lock on Gdk. Many Gtk+ ports don't do this automatically.

Syx used gtk_main() into a thread and automatically put gdk enter/leave for each function in its wrapper. It would be somewhat ugly in Smalltalk code having to enter/leave each time.
Of course, on Windows everything leads to troubles with threads.

But Smalltalk has Processes, handled by an internal scheduler. I decided then to not create a thread but cycle through Gtk+ events in the scheduler itself. Now everything works correctly.

Difference with other wrappers? The way Smalltalk is thought let you perform multi-tasking without the need to use OS threads, which means no problems on Windows and no need to take care of the Gdk lock everytime.

In addition, I rewrote part of the Console (Smalltalk-side) to be asyncronous using Semaphores. Now you can work on widgets after you run Gtk main! A small example:

Smalltalk YX 0.1.7 is ready.
Type "help!" to get help.
> Smalltalk loadPlugin: 'gtk'!
> | w |
> w := GtkWindow new.
> Gtk main.
> w add: (GtkLabel new: 'hello').
> w showAll!
a GtkWindow
You can imagine the result ;)
If you want to try it out you can download the scheduler branch snapshot.

Stay tuned for next 0.1.7 release.


Anonymous said...
This comment has been removed by a blog administrator.
Anonymous said...


good stuff, looking foward to trying that out.

pandith13 said...

Nice Post! I liked it.