... continued

In the previous sections, we worked with wait() and notify() methods. These methods have closely related cousins which take in parameters. We discuss them as follows:

wait(n)

The wait(n) method takes in a floating point parameter n. This is the number of seconds a calling thread would wait to be notified by another thread. The wait method times out after n seconds and the thread is woken up even if no notification is received. Consider the below snippet:

Using wait(n)

from threading import Condition
from threading import Thread
import time

flag = False

cond_var = Condition()


def child_task():
    cond_var.acquire()

    if (flag == False):
        cond_var.wait(1)

    if (flag == False):
        print("child thread times out waiting for a notification")

    # don't forget to release the lock    
    cond_var.release()


thread = Thread(target=child_task)
thread.start()

time.sleep(3)
thread.join()

Note that we have digressed from the idiomatic usage of the wait method by not testing for the condition in a while ...