python中locked

Python Lock.locked()方法 (Python Lock.locked() Method)

locked() is an inbuilt method of the Lock class of the threading module in Python.

Locked()是Python中线程模块的Lock类的内置方法。

This method returns True if the lock is acquired by a thread else returns False.

如果线程获取了锁，则此方法返回True ，否则返回False 。

Module:

模块：

    from threading import Lock

Syntax:

句法：

    locked()

Parameter(s):

参数：

• None

  没有

Return value:

返回值：

The return type of this method is <class 'bool'>. It returns True is the lock is currently acquired else returns False.

此方法的返回类型为<class'bool'> 。 返回True是当前获取的锁，否则返回False 。

Example:

例：

# Python program to show
# the use of locked() method in Lock class
import threading
import random
class shared(object):
def __init__(self, x = 0):
# Created a Lock object
self.lock = threading.Lock()
self.incr = x
# Increment function for the thread
def incrementcounter(self):
print("Waiting for the lock to be unlocked")
# Lock acquired by the current thread
self.lock.acquire()
print("Is the lock acquired here:", self.lock.locked())
try:
print('Lock acquired, current counter value: ', self.incr)
self.incr = self.incr + 1
print("Is the lock acquired here as well:", self.lock.locked())
finally:
print('Lock released, current counter value: ', self.incr)
# Lock released by the given thread
self.lock.release()
print("Is the lock acquired here after release:", self.lock.locked())
def helper_thread(c):
# Getting a random integer between 1 to 3
r = random.randint(1,3)
print("Random value selected:", r)
for i in range(r):
c.incrementcounter()
print('Finished', str(threading.current_thread().getName()))
print()
if __name__ == '__main__':
obj = shared()
thread1 = threading.Thread(target=helper_thread, args=(obj,))
thread1.start()
thread2 = threading.Thread(target=helper_thread, args=(obj,))
thread2.start()
thread1.join()
thread2.join()
print('Final counter value:', obj.incr)

Output

输出量

Waiting for the lock to be unlocked
Is the lock acquired here: True
Lock acquired, current counter value:  0
Is the lock acquired here as well: True
Lock released, current counter value:  1
Is the lock acquired here after release: False
Finished Thread-1
Random value selected: 3
Waiting for the lock to be unlocked
Is the lock acquired here: True
Lock acquired, current counter value:  1
Is the lock acquired here as well: True
Lock released, current counter value:  2
Is the lock acquired here after release: False
Waiting for the lock to be unlocked
Is the lock acquired here: True
Lock acquired, current counter value:  2
Is the lock acquired here as well: True
Lock released, current counter value:  3
Is the lock acquired here after release: False
Waiting for the lock to be unlocked
Is the lock acquired here: True
Lock acquired, current counter value:  3
Is the lock acquired here as well: True
Lock released, current counter value:  4
Is the lock acquired here after release: False
Finished Thread-2
Final counter value: 4

翻译自: https://www.includehelp.com/python/lock-locked-method-with-example.aspx

python中locked