Pipe
multiprocessing.Pipe()即管道模式，调用Pipe()返回管道的两端的Connection。
pipe()方法返回的是一个tuple（conn1，conn2）；
Pipe方法还有一个参数duplex参数，如果deplex=True,叫双工模式;deplex=False单工模式，那么返回的参数conn1只负责接受，conn2只负责发信息。
主要方法：
（1）send() 发信息
（2）rece()接受信息
（3）close()关闭管道
例子（1）单进程
from multiprocessing import Pipe,Process
def son_process(x,pipe):
_out_pipe,_in_pipe = pipe
while x:
try:
#recv 接受信息
msg = _out_pipe.recv()
print(msg)
x = x-1
except EOFError:
break
if __name__ == '__main__':
out_pipe,in_pipe = Pipe(True)
son_p = Process(target=son_process,args=(10,(out_pipe,in_pipe)))
son_p.start()
#out_pipe,close()
for x in range(10):
#send 发信息
in_pipe.send(x)
son_p.join()
print("主进程也结束了")
运行结果：
0
1
2
3
4
5
6
7
8
9
主进程也结束了
例子（2）多进程之间通讯
import time
import multiprocessing
from multiprocessing import Process
def proc1(pipe):
for i in range(10):
print("send {0}".format(i))
pipe.send(i)
time.sleep(0.1)
def proc2(pipe):
n = 10
while n:
print("proc2 recv: {0}".format(pipe.recv()))
n -= 1
if __name__ == '__main__':
(p1, p2) = multiprocessing.Pipe(duplex=False)
pr = Process(target=proc1, args=(p2,))
cu = Process(target=proc2, args=(p1,))
pr.start()
cu.start()
运行结果：
send 0
proc2 recv: 0
send 1
proc2 recv: 1
send 2
proc2 recv: 2
send 3
proc2 recv: 3
send 4
proc2 recv: 4
send 5
proc2 recv: 5
send 6
proc2 recv: 6
send 7
proc2 recv: 7
send 8
proc2 recv: 8
send 9
proc2 recv: 9
multiprocessing.Queue 队列
from Queue import Queue
常用方法
Queue(maxsize=0) 指定队列大小，0表示无限
q = Queue()
q.qsize() #返回当前队列的空间
q.empty() #判断当前队列是否为空
q.full() #判断当前队列是否满
q.put() #放消息
q.get() #获取消息
q.task_done() #接受消息的线程调用该函数来说明消息对应的任务是否已经完成
q.join() #等待队列为空，在执行别的操作
例子
from multiprocessing import Queue,Pipe
from threading import Thread
import time
#生产
def produce(q):
print("start produce")
for i in range(10):
q.put(i) #放入消息
print("produce has produced value {0}".format(i))
time.sleep(0.3)
print("end produce")
#消费
def custome(q):
print("start custorme")
while True:
data = q.get() #获取消息
print("custormer has get value{0}".format(data))
if __name__ =="__main__":
q = Queue()
p = Thread(target=produce,args=(q,))
c = Thread(target=custome,args=(q, ))
p.start()
c.start()
运行结果：
start produce
start custorme
produce has produced value 0
custormer has get value0
produce has produced value 1
custormer has get value1
produce has produced value 2
custormer has get value2
produce has produced value 3
custormer has get value3
produce has produced value 4
custormer has get value4
produce has produced value 5
custormer has get value5
produce has produced value 6
custormer has get value6
produce has produced value 7
custormer has get value7
produce has produced value 8
custormer has get value8
produce has produced value 9
custormer has get value9
end produce
