if__name__=="__main__":lock=ReadWriteLock()# 创建锁对象# 创建多个线程进行读写操作threads=[]for_inrange(5):# 创建5个读者线程threads.append(threading.Thread(target=read_file,args=(lock,)))threads.append(threading.Thread(target=write_file,args=(lock,)))# 创建1个写者线程# 启动所有线程f...
不必多说,用Python实现的读写锁(ReadWriteLock):允许同时多个reader,但只能有一个writer,并且writer工作时reader也不能读 代码说明: 1.实现方法和其他语言没有太大区别,这里threading模块是python实现的高级多线程模块(相对low-level的thread模块而言) 2.python中的condition信号量对象其实还被委托了lock的一些列操作,...
importmultiprocessingimporttimeimportrandom# 创建读写锁classReadWriteLock:def__init__(self):self.read_lock=multiprocessing.Lock()self.write_lock=multiprocessing.Lock()self.readers=0defstart_read(self):withself.read_lock:self.readers+=1ifself.readers==1:# 第一个读者上锁self.write_lock.acquire()de...
=0:self.writers_waiting+=1writers_ok=threading.Condition(self.monitor)self.wait_writers_q.put(writers_ok)writers_ok.wait()self.writers_waiting-=1self.rwlock=-1self.monitor.release()defpromote(self):"""Promote an already-acquired read lock to a write lockWARNING:it is very easy to deadlock...
self.cnt =0self.extra = threading.Lock()defread_acquire(self):withself.extra: self.cnt +=1ifself.cnt ==1: self.lock.acquire()defread_release(self):withself.extra: self.cnt -=1ifself.cnt ==0: self.lock.release()defwrite_acquire(self): ...
globaltodayread_marker=marker.gen_rlock()name='Reader-'+str(id_number)whiletoday<len(WEEKDAYS)-1:read_marker.acquire()print(name,'sees that today is',WEEKDAYS[today],'-read count:',read_marker.c_rw_lock.v_read_count)read_marker.release()defcalender_writer(id_number):globaltodaywrite_...
Lock() self.read_num = 0 def read_acquire(self): with self._extra: self.read_num += 1 if self.read_num == 1: self._lock.acquire() def read_release(self): with self._extra: self.read_num -= 1 if self.read_num == 0: self._lock.release() def write_acquire(self): self....
import java.util.concurrent.locks.ReadWriteLock; import java.util.concurrent.locks.ReentrantReadWriteLock; public class Resource <E> { private ReadWriteLock lock = new ReentrantReadWriteLock(); private E data; public void set(E e) { this.lock.writeLock().lock(); //获得写锁 //其他线程不...
LOCK_MAND:它主要是用于共享模式强制锁,它可以与 LOCK_READ 或者 LOCK_WRITE联合起来使用,从而表示是否允许并发的读操作或者并发的写操作 demo importfcntlimportthreadingimporttimedefwritetoTxt(txtFile):id= threading.currentThread().getName()withopen(txtFile,'a')asf: ...
lock.release() 当然为了支持在同一线程中多次请求同一资源,Python 提供了可重入锁(RLock)。RLock 内部维护着一个 Lock 和一个 counter 变量,counter 记录了 acquire 的次数,从而使得资源可以被多次 require。直到一个线程所有的 acquire 都被 release,其他的线程才能获得资源。