# test capability for threads to access a shared mutable data structure
# (without contention because they access different parts of the structure)
#
# MIT license; Copyright (c) 2016 Damien P. George on behalf of Pycom Ltd

import _thread

def foo(lst, i):
 lst[i] += 1

def thread_entry(n, lst, idx):
 for i in range(n):
 foo(lst, idx)
 with lock:
 global n_finished
 n_finished += 1

lock = _thread.allocate_lock()
n_thread = 2
n_finished = 0

# the shared data structure
lst = [0, 0]

# spawn threads
for i in range(n_thread):
 _thread.start_new_thread(thread_entry, ((i + 1) * 10, lst, i))

# busy wait for threads to finish
while n_finished < n_thread:
 pass
print(lst)