python使用Ctrl+C中断threading多线程死循环及setDaemon守护进程
threading多线程，没有提供线程退出的方法。
如果在死循环多线程，则即使CTRL+C也没有任何效果：
例如：
#coding=utf8
import threading
import time
def showperson(name):
while True:
time.sleep(1)
print 'show person :%s'%name
print '%s thread start!'%(time.ctime())
list=[]
for i in range(3):
t =threading.Thread(target=showperson,args=("person-%d"%i,))
list.append(t)
t.start()
for threadinglist in list:
threadinglist.join()
print '%s thread end!'%(time.ctime())输出：
[root@myrpc zrd]# python threadkill.py
Fri May 26 22:38:37 2017 thread start!
show person :person-0
show person :person-1
show person :person-2
^C^Cshow person :person-0
show person :person-1
show person :person-2
^C^C^C^Cshow person :person-0
show person :person-1
show person :person-2
^C^C^C^Cshow person :person-0
show person :person-1
show person :person-2
^C^C^C^C^Cshow person :person-1
show person :person-0
show person :person-2
^C^C^C^C^Cshow person :person-1
show person :person-0
show person :person-2
show person :person-1最后只有kill进程才能退出：
# ps -ef | grep python
root 1781 1635 0 May25 pts/1 00:00:00 python
root 1824 1635 0 May25 pts/1 00:00:00 python
root 5479 5451 0 22:04 pts/2 00:00:00 python
root 5576 5550 0 22:38 pts/3 00:00:00 python threadkill.py
root 5600 5580 0 22:38 pts/4 00:00:00 grep python
kill -9 1781 1824 5479 5576那怎么样才能退出呢，可以设置守护进程setDaemon
并且不能使用join将进程挂起，否则也无法退出，但是并不能使用join，则会重复上面的问题，
这里使用while空循环
修改如下：
#coding=utf8
import threading
import time
def showperson(name):
while True:
time.sleep(1)
print 'show person :%s'%name
print '%s thread start!'%(time.ctime())
list=[]
for i in range(3):
t =threading.Thread(target=showperson,args=("person-%d"%i,))
list.append(t)
t.setDaemon(True)
t.start()
while True:
pass
print '%s thread end!'%(time.ctime())输出：
# python threadkill.py
Fri May 26 22:47:17 2017 thread start!
show person :person-0
show person :person-1
show person :person-2
^CTraceback (most recent call last):
File "threadkill.py", line 19, in <module>
while True:
KeyboardInterrupt使用CTRL+C退出了程序，但是抛出一个异常
解决方法
1.设置异常处理，抛出一个提示程序退出
#coding=utf8
import threading
import time
def showperson(name):
while True:
time.sleep(1)
print 'show person :%s'%name
print '%s thread start!'%(time.ctime())
try:
list=[]
for i in range(3):
t =threading.Thread(target=showperson,args=("person-%d"%i,))
list.append(t)
t.setDaemon(True)
t.start()
while True:
pass
except KeyboardInterrupt,e:
print "you stop the threading"
print '%s thread end!'%(time.ctime())输出：
# python threadkill.py
Fri May 26 23:01:00 2017 thread start!
show person :person-0
show person :person-1
show person :person-2
^Xshow person :person-0
show person :person-1
show person :person-2
^X^X^X^Xshow person :person-0
show person :person-1
show person :person-2
^A^A^Ashow person :person-0
show person :person-1
show person :person-2
^Cyou stop the threading
Fri May 26 23:01:15 2017 thread end!CTRL+c的时候才退出
2.编写quit退出，使用signal信号传递
#coding=utf8
import threading
import time
import sys
import signal
def showperson(name):
while True:
time.sleep(1)
print 'show person :%s'%name
print '%s thread start!'%(time.ctime())
def quit(signal_num,frame):
print "you stop the threading"
sys.exit()
try:
signal.signal(signal.SIGINT, quit)
signal.signal(signal.SIGTERM, quit)
list=[]
for i in range(3):
t =threading.Thread(target=showperson,args=("person-%d"%i,))
list.append(t)
t.setDaemon(True)
t.start()
while True:
pass
except Exception,e:
print e
print '%s thread end!'%(time.ctime())结果：
Fri May 26 23:10:43 2017 thread start!
show person :person-0
show person :person-1
show person :person-2
show person :person-0
show person :person-1
show person :person-2
^Cyou stop the threading但是这个退出，不会进行后面的步骤，而之前的异常捕获处理后会进行后续步骤