Re: GTK and tasking (GNAT)

[hreba <hreba@terra.com.br>]

On 05/03/2014 06:23 PM, Simon Wright wrote:
> hreba <hreba@terra.com.br> writes:
>
>>              accept StartCounter (txtBox: Gtk.GEntry.Gtk_Entry) do
>>                 for i in 1..10 loop
>>                    Gtk.GEntry.Set_Text (txtBox, Integer'Image(i));
>>                    Gtk.Widget.Queue_Draw (Gtk.Widget.Gtk_Widget(txtBox));
>>                    delay 0.5;
>>                 end loop;
>>              end StartCounter;
>
> The calling task (probably the Gtk main loop) blocks while the body of
> the accept statement is executed.
>
> I don't know how this ought to be done in Gtk, though I strongly suspect
> it's not like that! However, the way to deal with the task problem would
> normally be to save the values passed with the accept and deal with them
> afterward:
>
>     accept StartCounter (txtBox: Gtk.GEntry.Gtk_Entry) do
>        txtBoxCopy := txtBox;
>     end StartCounter;
>     --  Now the caller can carry on while we work with the passed value.
>     for i in 1..10 loop
>        Gtk.GEntry.Set_Text (txtBoxCopy, Integer'Image(i));
>        Gtk.Widget.Queue_Draw (Gtk.Widget.Gtk_Widget(txtBoxCopy));
>        delay 0.5;
>     end loop;
>
> Questions: is Gtk thread-safe? is Queue_Draw something that should only
> be called from the Gtk event queue?
>

I didn't expect that my first excursion into GUI programming (GTK) with 
Ada would confront me with tasking and lead me into the cliffs of 
thread-safety.

I am no software engineer, unfortunately I cannot answer these questions.

So I will have a look at Dimitry's library.

Thanks for the answer.
-- 
Frank Hrebabetzky		+55 / 48 / 3235 1106
Florianopolis, Brazil