import threading
import time

g_num = 0


def test1(num):
    global g_num
    for i in range(num):
        mutex.acquire()  # 上锁
        g_num += 1
        mutex.release()  # 解锁

    print("---test1---g_num=%d" % g_num)


def test2(num):
    global g_num
    for i in range(num):
        mutex.acquire()  # 上锁
        g_num += 1
        mutex.release()  # 解锁

    print("---test2---g_num=%d" % g_num)


# 创建一个互斥锁
# 默认是未上锁的状态
mutex = threading.Lock()

# 创建2个线程，让他们各自对g_num加1000000次
p1 = threading.Thread(target=test1, args=(1000000,))
p1.start()

p2 = threading.Thread(target=test2, args=(1000000,))
p2.start()

# 等待计算完成
while len(threading.enumerate()) != 1:
    time.sleep(1)

print("2个线程对同一个全局变量操作之后的最终结果是:%s" % g_num)
