Semaphore in threading

import threading, time, sys

sem = threading.Semaphore(3)

def foobar(n):

with sem:

print(n, sem._value, end=" | ")

sys.stdout.flush()

time.sleep(2)

threads = []

for counter in range(20):

th = threading.Thread(target=foobar, args=(counter, ))

th.start()

threads.append(th)

for th in threads:

th.join()

Ausgabe:

0 2 | 1 1 | 2 0 | 3 0 | 4 0 | 5 0 | 7 1 | 6 0 | 8 0 |

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