import java.util.concurrent.locks.Lock; import java.util.concurrent.locks.ReentrantLock; public class SleepDemo { //创建一个独占锁 private static final Lock lock = new ReentrantLock(); public static void main(String[] args) throws InterruptedException{ //线程…
我们常用的synchronized关键字是一种最简单的线程同步控制方法,它决定了一个线程是否可以访问临界区资源.同时Object.wait() 和Object.notify()方法起到了线程等待和通知的作用.这些工具对于实现复杂的多线程协作起到了重要的作用. 这里,我们介绍一种synchronized,Object.wait() 和Object.notify()方法的替代品--重入锁.首先看下重入锁的例子: public ReentrantLock lock = new Re…
不多解释,预防普通锁不正规的获取与释放 #!/usr/bin/env python # -*- coding: utf-8 -*- import threading import time class MyThread(threading.Thread): def run(self): global num time.sleep(1) if mutex.acquire(1): num += 1 msg = self.name + ' set num to ' + str(num) print m…
一. POSIX 中对可重入和线程安全这两个概念的定义: Reentrant Function:A function whose effect, when called by two or more threads,is guaranteed to be as if the threads each executed the function one after another in an undefined order, even if the actual execution is inte…
Writing Reentrant and Thread-Safe Code 编写可重入和线程安全的代码 (http://www.ualberta.ca/dept/chemeng/AIX-43/share/man/info/C/a_doc_lib/aixprggd/genprogc/writing_reentrant_thread_safe_code.htm) In single-threaded processes there is only one flow of control. The…
对于线程重入,在C#中有lock关键字锁住一个SyncObject,而SQL Server也可用一个表来模拟实现. 先创建一个同步表,相当于C#中的SyncObject,并插入一条记录(初始值为1) create table SyncTable(id bit) go ) 然后假设有个存储过程,有一系列操作,需要防止多线程同时访问到,可以这样写. SET ANSI_NULLS ON GO SET QUOTED_IDENTIFIER ON GO create PROCEDURE Proc_Tes…
