Re: Question about type casting.

Thanks a lot for clearify this matter. So the bottom line is when there is no mention
about the type of widget in argument we can use GtkWidget there, right?

From: Tristan Van Berkom <tristan van berkom gmail com>
To: DC A <adc4444 hotmail com>
CC: gtk-list gnome org
Subject: Re: Question about type casting.
Date: Sat, 08 Oct 2005 01:23:51 -0400

DC A wrote:

Why we cast for the first argument of this function but not the second one?

It seems a little wierd, but eventually you find that its just easier to
generalize where you can:

/* gtk_button_new & gtk_vbox_new return `GtkWidget *',
 * not `GtkButton *'
GtkWidget *vbox   = gtk_vbox_new (FALSE, 0);
GtkWidget *button = gtk_button_new ();

/* Here we cast our `GtkWidget *vbox' to GTK_BOX to suit
 * the api, most gtk functions take GtkWidget arguments
 * (well, at least most container implementations do), so
 * its just easier to declare every widget as `GtkWidget *'
 * and not its subclass.
gtk_box_pack_start (GTK_BOX (vbox), button, TRUE, TRUE, 0);


[Date Prev][Date Next]   [Thread Prev][Thread Next]   [Thread Index] [Date Index] [Author Index]