Message Attributes
******************

Each message in a folder has a set of attributes that VM will remember
from session to session.  Various VM commands set and unset these
attributes.  Here are the attributes maintained by VM.

`new'
     The message was retrieved from a spool file during this visit of
     the current folder.
`unread'
     The message was retrieved from a spool file during some past
     visit of the folder but is still unread.
`filed'
     The message has been saved to some folder.
`written'
     The body of the message has been saved to a file.
`edited'
     The message has been altered (with `vm-edit-message') since it
     arrived.
`deleted'
     The message is deleted and will be removed from the folder at the
     next expunge.
`forwarded'
     The message has been forwarded with either `vm-forward-message'
     or `vm-send-digest'.
`redistributed'
     The message has been forwarded with the `vm-resend-message'
     command.
`replied'
     The message has been replied to.

You can set and unset these attributes directly by using `a'
(`vm-set-message-attributes').  You will be prompted in the minibuffer
for names of the attributes and you can enter them with completion.
Every attribute have an "un-" prefixed name you can use to unset the
attribute, excepting "new" and "unread", which are both negated by
"read".  You can use a prefix arugment with this command to affect
multiple messages, and you can apply this command to marked messages
with `M N'.

VM provides a special form of undo which allows changes to message
attributes to be undone.  Typing `C-x u' or C-_ (`vm-undo') undoes the
last attribute change.  Consecutive `vm-undo''s undo further and
further back.  Any intervening command breaks the undo chain, after
which the undo's themselves become undoable by subsequent invocations
of `vm-undo'.

Note that expunges, saves and message edits are *not* undoable.

"Labels" are user-defined message attributes.  They can have any name
and be assigned any meaning by you.  Labels are added with `l a'
(`vm-add-message-labels' and `l e' (`vm-add-existing-message-labels',
and are removed by `l d' (`vm-delete-message-labels').  BABYL format
folders use labels to store basic attributed like "deleted" and
"unread".  When visiting a BABYL folder VM uses these labels also in
order to be compatible with other BABYL mailers.  The labels used are
"recent", "unseen", "deleted", "answered", "forwarded",
"redistributed", "filed", "edited" and "written".  If (and only if)
you are using BABYL format folder, you should not use these label
names for your own purposes.

All message attributes are stored in the folder.  In order for
attribute changes to be saved to disk, they must be written to the
folder's buffer prior to the buffer being saved.  The variable
`vm-flush-interval' control how often that is done.  A value of `t'
means write the new attributes to the folder buffer whenever a change
occurs.  A value of `nil' means wait until just before the folder is
saved before writing out the attributes.  VM will work faster with
this setting but if Emacs or your system crashes, the autosave file
will contain no useful data pertaining to message attribute changes.
The autosave file will still reflect message edits and expunges.
See Crash Recovery.  A positive integer value N instructs VM to
write out attribute changes every N seconds.  The default value of
this variable is `t'.