g_signal_connect() and G_OBJECT

[Ingo Brückl <ib wupperonline de>]

Hi,

it seems that it was common practice to cast the first argument of
g_signal_connect() to G_OBJECT when I started developing applications with
GTK+ quite a while ago. At least I've learned it that way and am doing it
ever since.

I repeatedly see usage of g_signal_connect() without that cast which seems
to make sense since "instance" only has to be a gpointer and will be checked
G_TYPE_CHECK_INSTANCE at run time.

So I'm just curious. Is/was there a reason for the G_OBJECT cast? Was it
necessary back in the days (when GTK+ 2 took over from GTK+ 1)?

Ingo