管道Pipe

管道是双向通信的，数据从其中一端传入，就会从另外一端传出。

from multiprocessing import Pipe

c1, c2 = Pipe()
c1.send(123)
print(c2.recv())  # 一端进去，从另一端接收。

在进程间通过管道实现通信。

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())

 多次发数据：

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)

另一种方式close():

from multiprocessing import Process
from multiprocessing import Pipe


def func(conn1, conn2):
    conn2.close()  # conn2传过来不用，直接关掉
    while 1:

        try:
            msg = conn1.recv()
            print(msg)
        except EOFError:  # 捕获这个报错，关掉conn1并结束.EOFError是没有数据了还要recv时报的错
            conn1.close()
            break


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