The queue directory consists of the following plural directories:
new/ active/ incoming/ deferred/ info/sender/ info/recipients/ info/transport/info/ stores envelope information. incoming/ holds incoming queue, others hold outgoing information.
In creating a new outgoing queue file, make a temporary file in new/ once. When the delivery preparation is ended, move the queue from new/ to active/. Hence files under active/ is delivery ready.
When we need to handle the specific queue file, use lock()/unlock() method for each $queue_id object. The lock algorithm is based on flock(2) for the file.
Copyright (C) 1993-2018 Ken'ichi Fukamachi mail:< fukachan at fml.org >