Re: problem using gtk_color_button_get_color

[Harring Figueiredo <harringf yahoo com>]

--- Andreas Madsack <gtk bol bb bawue de> wrote:

> Hello,
>
> when I used gtk_color_button_get_color 2 times I get a segfault.
> so I made a simple example with glade.
>
> here is the click-event for a button.
> when I click this button 2 times I get a segfault.
>
> void
> on_button1_clicked                     (GtkButton       *button,
>                                         gpointer         user_data)
> {
>   GdkColor *color;
>   GtkWidget *w;
>
>   w=lookup_widget (GTK_WIDGET (button), "colorbutton1");
>   gtk_color_button_get_color ((GtkColorButton *)w, color);
>
>   w=lookup_widget (GTK_WIDGET (button), "label1");
>   gtk_widget_modify_fg (w, GTK_STATE_ACTIVE, color);
>   gtk_widget_modify_fg (w, GTK_STATE_NORMAL, color);
>
> }


  You are lucky it does not core dump in the first call :P)

GdkColor *color;
GtkWidget *w;

   So far you have not allocated memory to any of the above variables, it is
pointing to lala land. Since you did not get a core dump on the first call, it 
is pointing to a memory area dedicated to your process.
     
>   gtk_color_button_get_color ((GtkColorButton *)w, color);

  and since there is no memory alocated, it will cause what you are getting.


  Here is how you likely want it done.

  GdkColor color;
  GtkWidget *w;   

    Make sure 'w' is pointng to a valid, already allocated widget (in this case
a GtkColorButton) (Perhaps you should add a check to see if glade found you
widget.)
   i.e.
   w=lookup_widget (GTK_WIDGET (button), "colorbutton1");
   g_return_if_fail(w != null);  
  /* down the road, this will save you a lot of grief when debuging if you
happend to change the name of the button! */


  gtk_color_button_get_color ((GtkColorButton *)w, &color);

  Now, it should work.

Regards,
Harring.


                
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