GTK+ provides tooltip functionality; you simply create a
GtkTooltips and attach it
to a widget. I like to use the following convenience
function in my applications:
set_tooltip(GtkWidget* w, const gchar* tip)
GtkTooltips* t = gtk_tooltips_new();
gtk_tooltips_set_tip (t, w, tip, NULL);
The GtkTooltips will be
destroyed along with the widget. Make your tooltips long
rather than short; there's no reason to skimp on the
amount of information you provide here. You should get in
the habit of calling
set_tooltip() every time you create a button or
other widget that could benefit from it.
Note that toolbars created from a GnomeUIInfo template will have
tooltips installed automatically.