gtk_idle_add error

[Keith Poole <platima gmail com>]

Hi.
Having some problems using gtk_idle_add.
Heres what im trying to do (its obvious)

// some function code here
    gtk_idle_add(idlestuff, window);
// some more function code here

int idlestuff(GtkWidget *widget, GtkWidget *window)
{
    gtk_window_set_position(GTK_WINDOW(window), GTK_WIN_POS_MOUSE);
    return TRUE;
}

I have tried all sorts and i cant get it to work at all. Gcc also spits out the following warning:
warning: implicit declaration of function 'gtk_idle_add'

Any help appreciated, thanks
-Keith Poole