Python - KeyboardInterrupt or RuntimeError implementation
<p>New to python and programming. I have a program consist of several classes, module and functions. the program runs from a main class which calls several modules and function</p>

<p>My question is how to implement keyboardinterrupt if the user wants to terminate a running program at any point. Do I need to implement 'try/except' method in all the functions? or this can be implementable in the main function? </p>

<p>To catch interrupt at any moment do I need to use try/except in all the calling functions?</p>

<pre><code>def KEYBOARD_INTERRUPT():
while True:
    yesnoinput=raw_input('Do you want to exit from software [Y/N]:') 
        if yesnoinput=='y' or yesnoinput.upper()=='Y':
            sys.exit()
        elif yesnoinput=='n' or yesnoinput.upper()=='N':
            break
        else:
            continue
def A():
    while True:
        try:
            userInput=raw_input("Please enter A")
            if userInput=='A':
                break
            else:
                continue
        except KeyboardInterrupt:
            KEYBOARD_INTERRUPT()

def B():

      userInput=raw_input("Please enter B")
      if userInput=='B':
            break
      else:
            continue

def main():
    try:
        A()
        B()
    except:
        KEYBOARD_INTERRUPT()
</code></pre>

<p>when main program is calling function B, at this moment if the user presses keyboardInterrupt the program will quit with error messgage, I am worried if I want to handle interrupt like KEYBOARD_INTERRUPT function I need to implement this in very function such as function A?</p>

<p>Did I understand wrong?  </p>

<p>You could do something like :</p>

<pre><code>try:
...
   except KeyboardInterrupt: 
       Do something
</code></pre>

python