Removed some #includes of stdio.h, ctype.h, stdlib.h, and

[nmh] / man / mh-sequence.man

diff --git a/man/mh-sequence.man b/man/mh-sequence.man
index f48f80d64257c1fe4307e3357105456338832cf1..8fbba7d2d3cc00b5f73eddf1e160fb6adee4f989 100644 (file)
--- a/man/mh-sequence.man
+++ b/man/mh-sequence.man
@@ -64,6 +64,14 @@ The interpretation of `n' may be overridden by preceding `n' with a
 plus or minus sign; `+n' always means up to `n' messages starting with
 `name', and `\-n' always means up to `n' messages ending with `name'.
 .PP
+Substituting `=' for `:' (i.e., \*(lqname=n\*(rq) will reduce the
+selection from a range of up to `n' messages, to a selection of
+just the `n'th message.  So for example, while \*(lqname:-3\*(rq
+selects the 3 messages ending with `name', \*(lqname=-3\*(rq selects
+just the 2nd previous message.  It is an error if the requested
+message does not exist (i.e., there aren't enough messages in the
+folder).
+.PP 
 In commands which accept a `msgs' argument, the default is either
 \*(lqcur\*(rq or \*(lqall\*(rq, depending on which makes more sense
 for each command (see the individual man pages for details).  Repeated
@@ -107,6 +115,15 @@ specification \*(lqname:cur\*(rq is not allowed (use just \*(lqcur\*(rq
 instead).  The syntax of these message range specifications is subject
 to change in the future.
 .PP
+Single messages (as opposed to ranges) may also be selected by
+substituting `=' for `:', as in \*(lqname=n\*(rq.  This will reduce
+the selection from being a range of up to `n' messages, to being a
+selection of just the `n'th message.  So while \*(lqseq:5\*(rq
+selects the first 5 messages of seqence `seq', \*(lqseq=5\*(rq
+selects just the 5th message of the sequence.  It is
+an error if the requested message does not exist (i.e., there aren't
+at least `n' messages in the sequence).
+.PP
 User-defined sequence names are specific to each folder.  They are
 defined using the
 .B pick
@@ -254,6 +271,36 @@ or
 displays a message, that message will be removed from
 any sequences named by the \*(lqUnseen\-Sequence\*(rq entry in the
 profile.
+.SS Sequence File Locking
+The \*(lqdatalocking\*(rq profile entry controls the type of locking used
+when reading and writing sequence files.  The locking mechanisms supported
+are detailed in
+.IR mh\-profile (5).
+This protects sequence file integrity when multiple
+.B nmh
+commands are run simultaneously.
+.B Nmh
+commands that modify the sequence file use transactional locks; the lock
+is held from the time the sequence file is read until it it written out.
+This ensures that modifications to the sequence file will not be lost
+if multiple commands are run simultaneously.  Long\-running
+.B nmh
+commands, such as
+.B inc
+and
+.BR pick ,
+will release the sequence lock during the bulk of their runtime and reread
+the sequence file after their processing is complete to reduce lock
+contention time.
+.PP
+.B Note:
+Currently transactional locks are
+.B only
+supported for public sequences; private sequences will not get corrupted, but
+the possibility exists that two
+.B nmh
+commands run simultaneously that add messages to a private sequence could result in
+one command's messages not appearing on the requested sequence.
 .SH FILES
 .fc ^ ~
 .nf