Function

Summary

Returns the owner of a lock.

Package

mp

Signature

lock-owner lock => result

Arguments

lock

A lock object

Values

result

A process, t or :unknown

Description

The lock-owner function returns the process that currently owns the lock, or nil .

If lock is a "sharing" lock then lock-owner checks for an exclusive lock (see lock-owned-by-current-process-p).

If lock is locked then result is normally the process that locked it. If lock was locked while multiprocessing was not running then result is t . Also, if lock was locked by an unknown process (for example, the process is killed whilst holding the lock) then result is :unknown .

result is nil if lock is not locked.

Example

CL-USER 1 > (let ((lock (mp:make-lock :name

                                      "my lock")))

              (mp:lock-owner lock))

NIL

CL-USER 2 > (let ((lock (mp:make-lock :name

                                      "my lock")))

              (mp:with-lock (lock)

                (mp:lock-owner lock)))

#<MP:PROCESS Name "CAPI Execution Listener 1" Priority 0 State "Running">

See also

lock-owned-by-current-process-p
make-lock
with-lock
process-lock
process-unlock
lock-name
lock-owned-by-current-process-p