Python进程之间全局变量不共享

from multiprocessing import *

list1 = []

def add_data():
    for i in range(3):
        list1.append(i)
    print('add ', list1)

def read_data():
    print('read ', list1)


if __name__ == '__main__':
    add = Process(target=add_data)
    read = Process(target=read_data)
    add.start()
    read.start()
    print('main', list1)

输出结果：
main []
add [0, 1, 2]
read []