On Mon, 2002-10-07 at 08:08, Amit Jain wrote: > > Hi All > I want to change label of a button.I got success in changing it but unable to >understand the meaning of that particular line which is written below > GTK_LABEL(GTK_BIN(button)->child) > Why should i first typecast button into GTK_BIN and again convert it into button >from GTK_BIN(button)->child. > I guess GTK_BIN(button)->child gives button object.am i right or doing some mistake >in interpreting the meaning of it. >
A GtkButton is a subclass of GtkBin. A GtkBin is a container subclass that contains only one child object (pointed to by the child field). So when you cast the button with GTK_BIN, you were doing this to access the child object. The child of a button is typically a GtkLabel but does not have to be. It could be a pixmap or a box containing a pixmap and a label. Unless you're positive its a label, you may want to test the child widget with a GTK_IS_LABEL(GTK_BIN(button)->child) before casting it as GTK_LABEL just to avoid GTK warnings. -- regards, Luciano Chavez [EMAIL PROTECTED] http://evms.sourceforge.net _______________________________________________ gtk-list mailing list [EMAIL PROTECTED] http://mail.gnome.org/mailman/listinfo/gtk-list
