Steven D'Aprano <st...@remove-this-cybersource.com.au> wrote: > On Mon, 06 Jul 2009 15:02:26 -0700, Michael Mossey wrote: > > > On Jul 6, 2:47 pm, Philip Semanchuk <phi...@semanchuk.com> wrote: > >> On Jul 6, 2009, at 5:37 PM, Michael Mossey wrote: > >> > >> > What is required in a python program to make sure it catches a > >> > control- > >> > c on the command-line? Do some i/o? The OS here is Linux. > >> > >> You can use a try/except to catch a KeyboardInterrupt exception, or you > >> can trap it using the signal > >> module:http://docs.python.org/library/signal.html > >> > >> You want to trap SIGINT. > >> > >> HTH > >> Philip > > > > Thanks to both of you. However, my question is also about whether I need > > to be doing i/o or some similar operation for my program to notice in > > any shape or form that Control-C has been pressed. In the past, I've > > written Python programs that go about their business ignoring Ctrl-C. > > I bet that somewhere in your code you have something like: > > > for x in really_big_list: > try: > long_running_process(x) > except: > continue > > > If that's what you're doing, stop! The correct way is: > > > for x in really_big_list: > try: > long_running_process(x) > except Exception: > # Let KeyboardInterrupt and SystemExit through. > continue
Note that it is a relatively recent change (in python 2.5) which made KeyboardInterrupt not a child of Exception n...@dogger:~$ python2.4 Python 2.4.6 (#2, Feb 17 2009, 20:01:48) [GCC 4.3.3] on linux2 Type "help", "copyright", "credits" or "license" for more information. Loaded customisations from '/home/ncw/.pystartup' >>> isinstance(KeyboardInterrupt(), Exception) True >>> n...@dogger:~$ python2.5 Python 2.5.4 (r254:67916, Feb 17 2009, 20:16:45) [GCC 4.3.3] on linux2 Type "help", "copyright", "credits" or "license" for more information. Loaded customisations from '/home/ncw/.pystartup' >>> isinstance(KeyboardInterrupt(), Exception) False >>> > for x in really_big_list: > try: > long_running_process(x) > except (KeyboardInterrupt, SystemExit): > print "User requested exit... shutting down now" > cleanup() > raise > except Exception: > continue That is the backwards compatible way -- Nick Craig-Wood <n...@craig-wood.com> -- http://www.craig-wood.com/nick -- http://mail.python.org/mailman/listinfo/python-list
