circuitpython/tests/thread/thread_shared1.py

# test capability for threads to access a shared immutable data structure
#
# SPDX-FileCopyrightText: Copyright (c) 2016 Damien P. George on behalf of Pycom Ltd
#
# SPDX-License-Identifier: MIT

import _thread

def foo(i):
    pass

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

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

# the shared data structure
tup = (1, 2, 3, 4)

# spawn threads
for i in range(n_thread):
    _thread.start_new_thread(thread_entry, (100, tup))

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