"""
Using Flag class for inter thread communication
multi thread example
"""
 
from time import sleep
import _thread
 
class Flag:
    run_core_1 = False
 
    @classmethod
    def set_run_flag(cls):
        cls.run_core_1 = True
 
    @classmethod
    def clear_run_flag(cls):
        cls.run_core_1 = False
 
    @classmethod
    def get_run_flag(cls):
        return cls.run_core_1
 
 
def core0_thread():
    counter = 0
    while True:
        # print next 5 even numbers
        for loop in range(5):
            print(counter)
            counter += 2
            sleep(1)
 
        # signal core 1 to run
        Flag.set_run_flag()
 
        # wait for core 1 to finish
        print("core 0 waiting")
        while Flag.get_run_flag():
            pass
 
 
def core1_thread():
    global run_core_1
    counter = 1
 
    while True:
 
        # wait for core 0 to signal start
        print("core 1 waiting")
        while not Flag.get_run_flag():
            pass
 
        # print next 3 odd numbers
        for loop in range(3):
            print(counter)
            counter += 2
            sleep(0.5)
 
        # signal core 0 code finished
        Flag.clear_run_flag()
 
 
Flag.clear_run_flag()
second_thread = _thread.start_new_thread(core1_thread, ())
core0_thread()