locking.c, locking.1: Make the protocol safe if the lockfile is (re)moved.

[misc] / locking.1

diff --git a/locking.1 b/locking.1
index 51837902af5c222e763919baf6687853b8be363a..a9a37aa52fee905b7df2e02803955744b81f8e35 100644 (file)
--- a/locking.1
+++ b/locking.1
@@ -97,6 +97,21 @@ for days, hours, minutes or seconds, respectively) for the lock to
 become available, and then give up.  This only makes sense with the
 .B \-\-wait
 option, so that is turned on automatically.
+.PP
+It is safe to unlink or atomically replace the lockfile while holding
+the lock, though these actions will release the lock immediately.  To
+safely delete the lockfile, for example, run
+.IP
+.B "locking lock rm lock"
+.PP
+Similarly, a file can be updated safely by
+.IP
+.nf
+.ft B
+locking file sh -c \e
+\h'8m'"update-file file >file.new && mv file.new file"
+.fi
+.ft R
 .SH "BUGS"
 The
 .B locking