Python 2.7：子线程不捕捉KeyboardInterrupt

Question

import sys 
import time 
import threading 

class exThread(threading.Thread): 
    def __init__(self, threadId): 
     threading.Thread.__init__(self) 
     self.threadId = threadId 

    def run(self): 
     try: 
      while 1: 
       pass 
     except KeyboardInterrupt: 
      print "Ctrl-C caught by thread" 
     finally: 
      print "Thread's finally clause being executed" 
      sys.exit() # Same as thread.exit() 

cond = True 
def func(): 
    pass 

try: 
    th = exThread(1) 
    th.start() 
    while True: 
     if cond: 
      func() 
except KeyboardInterrupt: 
    print "Ctrl-C caught by main thread" 
    sys.exit(0) 
finally: 
    print "Executing the finally clause from main thread" 

在执行上面的代码时，当我按下Ctrl-C时，主线程从其finally子句打印后退出。现在，由于子线程是非守护进程，它仍在try中运行：除KeyboardInterrupt块外。但是，这个子线程似乎没有响应Ctrl-C，即使它应该捕获KeyboardInterrupt异常。为什么？

Answer 1

据我所知，KeyboardInterrup只在主线程中引发。为了能够阻止其他线程，让他们不时检查一个事件，然后自动退出。

另一种选择是，以纪念子线程作为daemon=True，这样它会自动终止，当主线程终止：

th.daemon = True 

补充阅读：

• 如何守护线程工作Daemon Threads Explanation
• 但是，守护线程也可能是有害的：http://joeshaw.org/2009/02/24/605/