线程_互斥锁_Lock及fork创建子进程

"""
创建锁  mutex = threading.Lock()
锁定  mutex.acquire([blocking])
        当blocking为True时，当前线程会阻塞，直到获取到这个锁为止
        默认为True
        当blocking为False时，当前线程不会阻塞
释放  mutex.release()
"""
from threading import Thread,Lock
g_num = 0
def test1():
    global g_num
    for i in range(100000):
        mutexFlag = mutex.acquire(True)#通过全局变量进行调用函数
        # True会发生阻塞,直到结束得到锁为止
        if mutexFlag:
            g_num += 1
            mutex.release()
    print("test1--g_num = %d"%(g_num))
def test2():
    global g_num
    for i in range(100000):
        mutexFlag = mutex.acquire(True)
        if mutexFlag:
            g_num += 1
            mutex.release()
    print("----test2---g_num = %d "%(g_num))
mutex = Lock()
p1 = Thread(target=test1,)
# 开始进程
p1.start()
p2 = Thread(target=test2,)
p2.start()
print("----g_num = %d---"%(g_num))

---

fork创建子进程

import os
# fork()在windows下不可用
pid = os.fork()#返回两个值
# 操作系统创建一个新的子进程，复制父进程的信息到子进程中
# 然后父进程和子进程都会得到一个返回值，子进程为0，父进程为子进程的id号
if pid == 0:
    print("哈哈1")
else:
    print("哈哈2")

---

2020-05-07