using Gtk::Bin::get_child() to test for contents

[Rob Benton <rob benton conwaycorp net>]

Is it a good or reliable use of Gtk::Bin::get_child() to see if a widget 
 currently contains another widget?

if (frame.get_child() != NULL)
{
    g_print("we got something here\n");
}
else
{
    g_print("empty\n");
}