How to check if a GtkWidget pointer have been initialized?

[kai <tklam fieldtech com hk>]

Dear all,

In case, I want to save time and resource for creating  a group of widget.
Therefore, I want to avoid any re_generation or any dummy destroy.
A widget have been created, but how can I check if the widget pointer 
been initialized?

Any suggestion is appreciated.
Thanks,
Kai