Multiprocessing shared data

shared.py

#!/usr/bin/python
import ctypes
import multiprocessing
import random
import resource
import time

a = None

class Record(ctypes.Structure):
    _fields_ = [('value', ctypes.c_wchar_p)]
    def __init__(self, value):
        self.value = value

    def __str__(self):
        return '(%s)' % (self.value,)

def child(i):
    while True:
        print "%ik memory used in child %i: %s" % (resource.getrusage(resource.RUSAGE_SELF).ru_maxrss / 1024, i, a[i])
        time.sleep(1)
        for j in xrange(len(a)):
            c = a[j]

def main():
    global a
    #a = multiprocessing.Array(ctypes.c_wchar_p, [u'unicode %r!' % i for i in xrange(1000000)], lock=False)
    # Using c_wchar_p results in this output:
    # 363224k memory used in parent: unicode 0!
    # 72560k memory used in child 5: unicode 5!
    # 72556k memory used in child 3: unicode 3!
    # 72536k memory used in child 1: unicode 1!
    # 72568k memory used in child 4: unicode 4!
    # 72576k memory used in child 2: unicode 2!

    a = multiprocessing.Array(Record, [Record(u'unicode %r!' % i) for i in xrange(1000000)], lock=False)
    # Using Record results in this output:
    # 775892k memory used in parent: (key 0, unicode 0!)
    # 1936k memory used in child 5: (key 5, unicode 5!)
    # 1944k memory used in child 3: (key 3, unicode 3!)
    # 1940k memory used in child 4: (key 4, unicode 4!)
    # 1936k memory used in child 2: (key 2, unicode 2!)
    # 1948k memory used in child 1: (key 1, unicode 1!)
    for i in xrange(5):
        p = multiprocessing.Process(target=child, args=(i + 1,))
        p.start()
    while True:
        print "%ik memory used in parent: %s" % (resource.getrusage(resource.RUSAGE_SELF).ru_maxrss / 1024, a[0])
        time.sleep(1)
#        for j in xrange(len(a)):
#            c = a[j]

if __name__ == '__main__':
    main()