The purpose of this mail library is to provide a portable, efficient middleware for different kinds of mail access (IMAPrev4, POP3, NNTP, mbox, MH, Maildir).
You have two kinds of mailbox access, either using low-level functions with a different interface for each kind of access or using higher-level functions, using a driver to wrap the higher-level API. The API will be the same for each kind of mail access using the higher-level API.