"""

Exemple de 2 processus qui tournent en parallèle et échangent une variable avec Pipe.
https://docs.python.org/3/library/multiprocessing.html#exchanging-objects-between-processes

The Pipe() function returns a pair of connection objects connected
by a pipe which by default is duplex (two-way).
"""


import os
from multiprocessing import Process, Pipe


def test(n):
    """Fonction pour charger le processeur"""
    for i in range(n):
        m = (i ** 1.89999) ** 0.8974125


def first_processus(conn):
    print('first process:', os.getppid())
    a = 0
    while 1:
        test(1000000)
        a += 1
        print("a =", a)
        b = conn.recv()
        print("b dans first_process =", b)
        a += b[1]

def second_processus(conn):
    print('second process:', os.getppid())
    b = 0
    while 1:
        test(2000000)
        b += 5
        print("b dans second process =", b)
        conn.send(['b', b])


def main():
    """
    https://docs.python.org/3/library/multiprocessing.html#multiprocessing.Pipe
    multiprocessing.Pipe([duplex])
    If duplex is True (the default) then the pipe is bidirectional. If duplex is
    False then the pipe is unidirectional: conn1 can only be used for receiving
    messages and conn2 can only be used for sending messages.
    """
    parent_conn, child_conn = Pipe()
    p = Process(target=second_processus, args=(child_conn,))
    p.start()
    first_processus(parent_conn)


if __name__ == '__main__':
    main()