管道Pipe

管道是雙向通信的，資料從其中一端傳入，就會從另外一端傳出。

from multiprocessing import Pipe

c1, c2 = Pipe()
c1.send(123)
print(c2.recv())  # 一端進去，從另一端接收。      

在程序間通過管道實作通信。

from multiprocessing import Pipe
from multiprocessing import Process


def func(conn):
    conn.send(111)

if __name__ == "__main__":
    conn1, conn2 = Pipe()
    p = Process(target=func, args=(conn1,))
    p.start()
    print(conn2.recv())      

 多次發資料：

from multiprocessing import Process
from multiprocessing import Pipe


def func(conn):
    while 1:
        msg = conn.recv()
        if msg == None:break
        print(msg)


if __name__ == "__main__":
    conn1, conn2 = Pipe()
    Process(target=func, args=(conn1,)).start()
    for i in range(20):
        conn2.send(111)
    conn2.send(None)      

另一種方式close():

from multiprocessing import Process
from multiprocessing import Pipe


def func(conn1, conn2):
    conn2.close()  # conn2傳過來不用，直接關掉
    while 1:

        try:
            msg = conn1.recv()
            print(msg)
        except EOFError:  # 捕獲這個報錯，關掉conn1并結束.EOFError是沒有資料了還要recv時報的錯
            conn1.close()
            break


if __name__ == "__main__":
    conn1, conn2 = Pipe()
    Process(target=func, args=(conn1, conn2)).start()
    conn1.close()  # 關掉conn1
    for i in range(20):
        conn2.send(111)
    conn2.close()  # 關掉conn2