#
# proc1.py
#


# In the first Python interactive shell
import numpy as np
from multiprocessing import shared_memory

import time

a = np.array([1, 1, 2, 3, 5, 8])  # Start with an existing NumPy array

shm = shared_memory.SharedMemory(name='shmem', create=True, size=a.nbytes)
# Now create a NumPy array backed by shared memory
b = np.ndarray(a.shape, dtype=a.dtype, buffer=shm.buf)
b[:] = a[:]  # Copy the original data into shared memory

time.sleep(5) # Give me time to run the other program

# Clean up from within the first Python shell
del b  # Unnecessary; merely emphasizing the array is no longer used
shm.close()
shm.unlink()  # Free and release the shared memory block at the very end


#
# proc2.py
#

# In either the same shell or a new Python shell on the same machine
import numpy as np
from multiprocessing import shared_memory

# Attach to the existing shared memory block
existing_shm = shared_memory.SharedMemory(name='shmem')
# Note that a.shape is (6,) and a.dtype is np.int64 in this example
c = np.ndarray((6,), dtype=np.int64, buffer=existing_shm.buf)
c[-1] = 888

# Clean up from within the second Python shell
del c  # Unnecessary; merely emphasizing the array is no longer used
existing_shm.close()