How to determine if Gtk+ had been initialized

[Paul Plaquette <trilda free fr>]

Hi,

an application is using GTK+

It calls functions provide in a shared libary.

the library could present user interface based on GTK+ or not
depending on the application initialized Gtk+ or not (calling gtk-init 
()).

The question is : from the library, is there a way to know the caller  
had initialized Gtk+ ?

thanks
Paul