3.[python] Multi-thread routines Ctrl + C-Grace terminates __python

Reprint please indicate the original source: http://blog.csdn.net/a464057216/article/details/47678781

In multithreaded programming, there are often questions about how to gracefully stop a program, for example:

#!/usr/bin/env python
#-*-coding:utf-8-*
# written By-csdn:mars blog

import Loo, time

def PR IntA (): While
    true:
        print ' A '
        time.sleep (1)

def PRINTB (): While
    true:
        print ' B '
        Time.sleep (1)

if __name__ = = ' __main__ ':
    try:
        a = threading. Thread (target = PrintA)
        B = Threading. Thread (target = PRINTB)
        a.start ()
        B.start () a.join () B.join except () Exception
        , exc
    :
        Print Exc

Printa and PRINTB two threads are constantly 1s printing letters a and B, but such programs run up and down with CTRL + C to kill, only to shut down the terminal window or kill the process:

mars@mars-ideapad-v460:~/test$ python ctrl.py 
a
b
^c^ca
b
^c^ca
 b
^ca
 b
a
b

If you set up all two processes as daemons, you can use CTRL + C to terminate the program:

        # written By-csdn:mars Loo's blog

        a = threading. Thread (target = PrintA)
        B = Threading. Thread (target = PRINTB)
        A.setdaemon (True)
        A.start ()
        B.setdaemon (True)
        B.start () while

        True: Pass
            

Execution results:

mars@mars-ideapad-v460:~/test$ python ctrl.py
a
b
b
a
^ctraceback (most recent call last):
  File "ctrl.py", line, at <module> while
    True:
keyboardinterrupt

But the above method will also output ugly traceback information on the screen, and here's an elegant way to do this:

#!/usr/bin/env python
#-*-coding:utf-8-*
# written By-csdn:mars blog

import Loo, time, threading />import SYS

def printA (): While
    true:
        print ' A '
        time.sleep (1)

def PRINTB (): While
    true:
        print ' B '
        time.sleep (1)

def quit (Signum, frame):
    print ' You choose to stop me. '
    Sys.exit ()


if __name__ = = ' __main__ ':
    try:
        signal.signal (signal. SIGINT, quit)
        signal.signal (signal. Sigterm, quit)

        a = threading. Thread (target = PrintA)
        B = Threading. Thread (target = PRINTB)
        A.setdaemon (True)
        A.start ()
        B.setdaemon (True)
        B.start ()

        while True:
            pass
    except Exception, exc:
        print exc

Execution results:

mars@mars-ideapad-v460:~/test$ python ctrl.py 
a
b
 a b
^cyou choose to stop Me .

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