python多进程打印字符，加锁（Lock加锁）

先看不加锁的：

#coding=utf-8
from multiprocessing import Process,Lock
import time

def l(num):
    #lock.acquire()   
    #stime.sleep(2)
    print "Hello num:%s" %num
    #lock.release()

if __name__=='__main__':
    lock=Lock()
    for num in range(10):
        Process(target=l,args=(num,)).start()

结果：可以看到，启动10个进程，异步执行打印函数，打印的很乱

c:\Python27\Scripts>python task_test.py
HHello num:0Hello num:1
ello num:2
Hello num:3

HHello num:4ello num:5

Hello num:6
Hello num:7
Hello num:8
Hello num:9

加锁：

#coding=utf-8
from multiprocessing import Process,Lock
import time

def l(num,lock):
    lock.acquire()   
    #stime.sleep(2)
    print "Hello num:%s" %num
    lock.release()

if __name__=='__main__':
    lock=Lock()
    for num in range(10):
        Process(target=l,args=(num,lock)).start()

结果：执行打印的进程获得锁，打印后释放锁，之后下一个进程获得锁，所以每次打印都只有一个进程在操作

 c:\Python27\Scripts>python task_test.py
Hello num:0
Hello num:1
Hello num:3
Hello num:2
Hello num:6
Hello num:5
Hello num:4
Hello num:7
Hello num:8
Hello num:9