Copies mail messages specified by msglist to specified mailbox. 如果成功则返回 TRUE，失败则返回 FALSE。.
msglist is a range not just message numbers (as described in RFC2060).
options is a bitmask of one or more of
CP_UID - the sequence numbers contain UIDS
CP_MOVE - Delete the messages from the current mailbox after copying
See also imap_mail_move().