| Server IP : 188.40.95.74 / Your IP : 216.73.216.205 Web Server : Apache System : Linux cp01.striminghost.net 3.10.0-1160.119.1.el7.tuxcare.els13.x86_64 #1 SMP Fri Nov 22 06:29:45 UTC 2024 x86_64 User : vlasotin ( 1054) PHP Version : 5.6.40 Disable Function : NONE MySQL : ON | cURL : ON | WGET : ON | Perl : ON | Python : ON | Sudo : ON | Pkexec : ON Directory : /usr/share/doc/python-docs-2.7.5/html/_sources/library/ |
Upload File : |
:mod:`mutex` --- Mutual exclusion support ========================================= .. module:: mutex :synopsis: Lock and queue for mutual exclusion. :deprecated: .. deprecated:: 2.6 The :mod:`mutex` module has been removed in Python 3. .. sectionauthor:: Moshe Zadka <moshez@zadka.site.co.il> The :mod:`mutex` module defines a class that allows mutual-exclusion via acquiring and releasing locks. It does not require (or imply) :mod:`threading` or multi-tasking, though it could be useful for those purposes. The :mod:`mutex` module defines the following class: .. class:: mutex() Create a new (unlocked) mutex. A mutex has two pieces of state --- a "locked" bit and a queue. When the mutex is not locked, the queue is empty. Otherwise, the queue contains zero or more ``(function, argument)`` pairs representing functions (or methods) waiting to acquire the lock. When the mutex is unlocked while the queue is not empty, the first queue entry is removed and its ``function(argument)`` pair called, implying it now has the lock. Of course, no multi-threading is implied -- hence the funny interface for :meth:`lock`, where a function is called once the lock is acquired. .. _mutex-objects: Mutex Objects ------------- :class:`mutex` objects have following methods: .. method:: mutex.test() Check whether the mutex is locked. .. method:: mutex.testandset() "Atomic" test-and-set, grab the lock if it is not set, and return ``True``, otherwise, return ``False``. .. method:: mutex.lock(function, argument) Execute ``function(argument)``, unless the mutex is locked. In the case it is locked, place the function and argument on the queue. See :meth:`unlock` for explanation of when ``function(argument)`` is executed in that case. .. method:: mutex.unlock() Unlock the mutex if queue is empty, otherwise execute the first element in the queue.