resume execution after catching with an excepthook?

[Hans Mulder]

On 24/10/12 14:51:30, andrea crotti wrote:
> So I would like to be able to ask for confirmation when I receive a C-c,
> and continue if the answer is "N/n".
> 
> I'm already using an exception handler set with sys.excepthook, but I
> can't make it work with the confirm_exit, because it's going to quit in
> any case..
> 
> A possible solution would be to do a global "try/except
> KeyboardInterrupt", but since I already have an excepthook I wanted to
> use this.  Any way to make it continue where it was running after the
> exception is handled?
> 
> 
> def confirm_exit():
>     while True:
>         q = raw_input("This will quit the program, are you sure? [y/N]")
>         if q in ('y', 'Y'):
>             sys.exit(0)
>         elif q in ('n', 'N'):
>             print("Continuing execution")
>             # just go back to normal execution, is it possible??
>             break
> 
> 
> def _exception_handler(etype, value, tb):
>     if etype == KeyboardInterrupt:
>         confirm_exit()
>     else:
>         sys.exit(1)
> 
> 
> def set_exception_handler():
>     sys.excepthook = _exception_handler

I think the trick is to not use an except hook, but trap the
interrupt on a lower level.

This seems to work; I'm not sure how robust it is:

import signal

def handler(signum, frame):
    while True:
        q = raw_input("This will quit the program, are you sure? [y/N]")
        if q[:1] in "yY":
            raise KeyboardInterrupt
        elif q[:1] in "nN":
            print("Continuing execution")
            # just go back to normal execution
            return

signal.signal(signal.SIGINT, handler)


If you're debugging this on a Unix platform, it may help to know
that you can also kill a process with control-\

Hope this helps,

-- HansM