Re: [Vala] Idle.add lambda function with local variable

[Geert Jan <gj_alsem yahoo com>]

Sorry, forgot to mention I'm using Vala 0.7.9 from the Ubuntu PPA.

Also I just realized my example may not be the best, because in it I use an int instead of an object as I do 
in my real project. But anyway, my question still stands.


--- On Sun, 12/27/09, Geert Jan <gj_alsem yahoo com> wrote:

> From: Geert Jan <gj_alsem yahoo com>
> Subject: [Vala] Idle.add lambda function with local variable
> To: vala-list gnome org
> Date: Sunday, December 27, 2009, 5:16 PM
> Hi,
>
> I'm trying the following in Vala:
>
>
> public class Main : Object {
>
>   public static int main (string[] args) {
>
>     int x = 3;
>
>     Idle.add ( () => {
>       print ("%d\n", x);
>       x = 4;
>       return false;
>     });
>
>     for (int i = 0; i < 10; i++) {
>       Thread.usleep (100000);
>     }
>     print ("%d\n", x);
>
>     return 0;
>   }
> }
>
>
> It compiles, but with a warning:
>
>
> /media/Data/Code/Vala/valatest/lambda/main.vala.c: In
> function ‘main_main’:
> /media/Data/Code/Vala/valatest/lambda/main.vala.c:87:
> warning: passing argument 4 of ‘g_idle_add_full’ from
> incompatible pointer type
> /usr/include/glib-2.0/glib/gmain.h:291: note: expected
> ‘GDestroyNotify’ but argument is of type ‘void
> (*)(struct Block1Data *)’
>
>
> And when I run it, it only prints "3", when I expect it to
> print "3" and then "4".
>
> My question: is it possible to access a local variable in a
> lambda function like this? Or should I use a different
> method to pass a local variable to a function I want to add
> to Idle?
>
> (The reason I need to add something to Idle is because in
> my project I use Gtk and threads, and you shouldn't interact
> with Gtk elements from another thread.)
>
>
>
>       
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