| Allegro CL version 8.2 New since 8.2 release. |
Arguments: (sharable-lock &key yield-rate timeout) &body body
This macro was part of an early implementation of sharable locks. The
values returned are not consistent with other with-XXX macros
in Common Lisp. (with-exclusive-lock
returns t
rather than the value of the last
body form when the associated lock is acquired.) It is included for
compatibility with earlier versions. The recommended macro is
with-sharable-lock.
Evaluate a body of code in the context of a sharable-lock
acquired in exclusive mode.
The yield-rate argument, if specified,
must be a positive integer, or the keyword :never
.
The specified value overrides the value in the lock instance. If the
argument is omitted, or specified as nil
,
than the value in the lock instance is used.
The timeout argument, if specified, must be a non-negative number of seconds. The value determines how long the program will wait if the lock is not immediately available. A timeout value of zero specifies that that the lock must be available immediately only.
The recursive-p argument may be used to
override the recursion specification in the sharable-lock
instance. If
omitted, nil
or :default, the value in the
lock instance is used. Otherwise, the value must
be t
, one of the keywors allowed in
make-sharable-lock, or a list
of these keywords.
The body expressions are evaluated as a
progn body. If the lock is acquired, the body forms are evaluated,
and the with-exclusive-lock
expression returns a single value, t
. If the
lock is not acquired, the with-exclusive-lock expression returns two
values as described in sharable-lock-lock.
See Sharable locks in smp.htm.
See multiprocessing.htm for general information on multiprocessing in Allegro CL.
Copyright (c) 1998-2016, Franz Inc. Oakland, CA., USA. All rights reserved.
This page is new in the 8.2 release.
Created 2016.6.21.
| Allegro CL version 8.2 New since 8.2 release. |