numpy share memory in multiprocessing

share.py

import mmap
import numpy as np
import os
import time

rows, cols = 10, 8

mm = mmap.mmap(-1, rows * cols * 8)

a = np.ndarray((rows, cols), dtype=np.int64, buffer=mm)

pid = os.fork()

if pid == 0:  # In a child process
    time.sleep(1)
    print("child", a)
    exit(0)
else:
    a[0][0] = 1
    print("parent", a)
    time.sleep(3)