Re: GObject Singleton

[Stefan Kost <ensonic hora-obscura de>]

hi,

Uzytkownik wrote:
> I have singleton A and subclass B, C and D.
>
> 1. How do it in GObject?
The sigleton pattern is usually realized by having a factory method. The 
application would use e.g.
  gdk_display_manager_get()
which returns a reference to always the same GdkDisplayManager object. Such a 
class has no public gdk_display_manager_new() method. The implementation of the 
_get() method would use a static variable and create the instance on the first 
request to _get().

> 2. Can I do something that I cannot have B or D at the same time?

Not that I know. A base class has not controll over who subclasses them. What do 
you want to achieve. I am not aware of any OO system that could do that and I 
miss a cese where this would be needed.

Stefan