rmail-set-attribute

rmail-set-attribute is a compiled Lisp function in `rmail.el'.

(rmail-set-attribute ATTR STATE &optional MSGNUM)

Turn an attribute of a message on or off according to STATE.
STATE is either nil or the character (numeric) value associated
with the state (nil represents off and non-nil represents on).
ATTR is either the index number of the attribute, or a string,
both from `rmail-attr-array'. MSGNUM is message number to
change; nil means current message.