Re: Example in Docs: GPOINTER_TO_INT

["Daniel V." <dvenkita rand lab ecel uwa edu au>]

On Wed, May 30, 2001 at 07:15:36PM -0400, Brooklyn Linux Solutions wrote:
> Greeting
>
> What is GPOINTER_TO_INT in the example at:
>
> http://developer.gnome.org/doc/API/gtk/gtk-signals.html#GTK-SIGNAL-CONNECT
>
> ______________________________________________________________________________
> static void button_clicked_int(GtkButton* button, gpointer func_data)
>  {
>          g_print("button pressed: d\n", GPOINTER_TO_INT(func_data));
>  }
>
>  /* By calling this function, you will make the g_print above
>   * execute, printing the number passed as `to_print'. */
>  static void attach_print_signal(GtkButton* button, gint to_print)
>  {
>          gtk_signal_connect(GTK_OBJECT(button), "clicked",
>                  GTK_SIGNAL_FUNC(button_clicked_int),
>                  GINT_TO_POINTER(to_print));
>  }

It's a cast, from a pointer to an int.  Equivalent to:

(gint) to_print

The example puts an int in the pointer "slot" instead of a pointer, by
casting it to the pointer type.  It then retrieves the number by casting
the pointer back to an int.

Maybe not the best example, but commonly used nonetheless.

Daniel.
-- 
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Daniel Venkitachalam                                  venki-d ee uwa edu au
University of Western Australia                 swww.ee.uwa.edu.au/~venki-d
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