锁--互斥锁

# 抢票的例子
import json
from multiprocessing import Process, Lock
import time


def search_ticket_num(i):
    with open('ticket.txt', encoding='utf-8') as f:
        ticket = json.load(f)

    print(f"{i}号查询到当前的余票是{ticket['count']}张")


def pay_ticket(i):
    with open('ticket.txt', encoding='utf-8') as f:
        ticket = json.load(f)

    if ticket['count'] > 0:
        ticket['count'] -= 1
        print(f"{i}号买到了一张票")

    time.sleep(0.1)

    with open('ticket.txt', encoding='utf-8', mode='w') as f2:
        json.dump(ticket, f2)


def get_ticket(i, lock):
    search_ticket_num(i)

    with lock:  # 代替acquire和release，更加方便和安全
        pay_ticket(i)


if __name__ == '__main__':
    lock = Lock()  # 实例化一个锁对象
    for i in range(10):
        Process(target=get_ticket, args=(i, lock)).start()

互斥锁：

from multiprocessing import Lock


# 互斥锁：
#   即同一个进程中连续acquire多次

lock = Lock()

lock.acquire()
print(1)

lock.acquire()
print(2)