int imap_open(string mailbox, string username, string password, int flags);Returns an IMAP stream on success and false on error.
the options are a bit mask with noe or more of the following:
OP_READONLY - Open mailbox read-only
OP_ANONYMOUS - Dont use or update a .newsrc for news
OP_HALFOPEN - For IMAP and NNTP names, open a connection but dont open a mailbox
CL_EXPUNGE - Expunge mailbox automatically upon mailbox close