Sharing data between processes using Shared memory

multiprocessing module provides Array and Value objects to share data between processes.
Array: a ctypes array allocated from shared memory.
Value: a ctypes object allocated from shared memory.

import multiprocessing 

def square_list(mylist, result, square_sum): 
  """ 
  function to square a given list 
  """
  # append squares of mylist to result array 
  for idx, num in enumerate(mylist): 
    result[idx] = num * num 

  # square_sum value 
  square_sum.value = sum(result) 

  # print result Array 
  print("Result(in process p1): {}".format(result[:])) 

  # print square_sum Value 
  print("Sum of squares(in process p1): {}".format(square_sum.value)) 

if __name__ == "__main__": 
  # input list 
  mylist = [1,2,3,4] 

  # creating Array of int data type with space for 4 integers 
  result = multiprocessing.Array('i', 4) 

  # creating Value of int data type 
  square_sum = multiprocessing.Value('i') 

  # creating new process 
  p1 = multiprocessing.Process(target=square_list, args=(mylist, result, square_sum)) 

  # starting process 
  p1.start() 

  # wait until process is finished 
  p1.join() 

  # print result array 
  print("Result(in main program): {}".format(result[:])) 

  # print square_sum Value 
  print("Sum of squares(in main program): {}".format(square_sum.value))

References
https://www.geeksforgeeks.org/multiprocessing-python-set-2/

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