imap-authenticate

imap-authenticate is a compiled Lisp function in `imap.el'.

(imap-authenticate &optional USER PASSWD BUFFER)

Authenticate to server in BUFFER, using current buffer if nil.
It uses the authenticator specified when opening the server.

Optional arguments USER and PASSWD specify the username and
password to use if the authenticator requires a username and/or
password. If omitted or nil, the authenticator may query the
user for a username and/or password.