[Yahoo protocol] Appear permanently offline

[Tran The Anh]

I'm trying to write a plugin for Pidgin works with Yahoo protocol only.
Let's say I have a buddy list, I scan through the list and I need to
see if a buddy has the Presence is "Appear permanently offline".

Could somebody help me:
- which file(s) I need to #include in my plugin source code.
- which function should I pay more attention? (I already had my var:
PurpleBuddy* buddy)

Thanks so much