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Re: Python Front-end to GCC

References (8 earlier) <52669852$0$29981$c3e8da3$5496439d@news.astraweb.com> <l4667u$bke$2@reader1.panix.com> <5266aa80$0$29981$c3e8da3$5496439d@news.astraweb.com> <l46ahj$i4q$1@dont-email.me> <5266b496$0$29981$c3e8da3$5496439d@news.astraweb.com>
From Oscar Benjamin <oscar.j.benjamin@gmail.com>
Date 2013-10-22 18:37 +0100
Subject Re: Python Front-end to GCC
Newsgroups comp.lang.python
Message-ID <mailman.1364.1382463497.18130.python-list@python.org> (permalink)

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On 22 October 2013 18:23, Steven D'Aprano
<steve+comp.lang.python@pearwood.info> wrote:
> On Tue, 22 Oct 2013 16:53:07 +0000, Frank Miles wrote:
>
> [snip C code]
>> What you're missing is that arr[] is an automatic variable.  Put a
>> "static" in front of it, or move it outside the function (to become
>> global) and you'll see the difference.
>
> Ah, that makes sense. Thanks to everyone who corrected my
> misunderstanding.
>
> Well, actually, no it doesn't. I wonder why C specifies such behaviour?
> Why would you want non-global arrays to be filled with garbage?

It's not that you want them filled with garbage but rather that you
know you will fill them with useful values later and you don't want to
waste time pre-filling them with zeros first. Or perhaps you have some
other way of knowing which values are to be considered initialised.
This is reasonable in some contexts.

OTOH why in particular would you want to initialise them with zeros? I
often initialise arrays to nan which is useful for debugging. It means
that you can see if you made a mistake when you were supposed to have
initialised everything to useful values. In many contexts it would be
difficult to distinguish between a valid zero and a zero because you
haven't yet inserted a value. This kind of error can show up more
quickly if you don't zero the memory since the uninitialised values
will often be out of range for what you expected and will give very
noticeable results (such as a seg-fault).


Oscar

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Python Front-end to GCC Philip Herron <herron.philip@googlemail.com> - 2013-10-20 10:56 -0700
  Re: Python Front-end to GCC victorgarcianet@gmail.com - 2013-10-20 15:10 -0700
    Re: Python Front-end to GCC John Nagle <nagle@animats.com> - 2013-10-22 23:48 -0700
      Re: Python Front-end to GCC Philip Herron <herron.philip@googlemail.com> - 2013-10-23 00:25 -0700
        Re: Python Front-end to GCC Mark Lawrence <breamoreboy@yahoo.co.uk> - 2013-10-23 09:42 +0100
        Re: Python Front-end to GCC John Nagle <nagle@animats.com> - 2013-10-23 13:51 -0700
  Re: Python Front-end to GCC Mark Janssen <dreamingforward@gmail.com> - 2013-10-20 20:35 -0700
    Re: Python Front-end to GCC Steven D'Aprano <steve@pearwood.info> - 2013-10-21 07:46 +0000
      Re: Python Front-end to GCC Oscar Benjamin <oscar.j.benjamin@gmail.com> - 2013-10-21 10:55 +0100
        Re: Python Front-end to GCC Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2013-10-21 23:41 +0000
          Re: Python Front-end to GCC Oscar Benjamin <oscar.j.benjamin@gmail.com> - 2013-10-22 10:14 +0100
            Re: Python Front-end to GCC Philip Herron <herron.philip@googlemail.com> - 2013-10-22 02:32 -0700
            Re: Python Front-end to GCC Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2013-10-22 12:00 +0000
              Re: Python Front-end to GCC Chris Angelico <rosuav@gmail.com> - 2013-10-22 23:20 +1100
                Re: Python Front-end to GCC Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2013-10-22 17:27 +0000
                Re: Python Front-end to GCC Chris Angelico <rosuav@gmail.com> - 2013-10-23 08:43 +1100
              Re: Python Front-end to GCC Dave Angel <davea@davea.name> - 2013-10-22 14:04 +0000
                Re: Python Front-end to GCC Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2013-10-22 15:22 +0000
                Re: Python Front-end to GCC Grant Edwards <invalid@invalid.invalid> - 2013-10-22 15:39 +0000
                Re: Python Front-end to GCC Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2013-10-22 16:40 +0000
                Re: Python Front-end to GCC Mark Lawrence <breamoreboy@yahoo.co.uk> - 2013-10-22 17:50 +0100
                Re: Python Front-end to GCC Chris Kaynor <ckaynor@zindagigames.com> - 2013-10-22 09:52 -0700
                Re: Python Front-end to GCC Frank Miles <fpm@u.washington.edu> - 2013-10-22 16:53 +0000
                Re: Python Front-end to GCC Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2013-10-22 17:23 +0000
                Re: Python Front-end to GCC Chris Kaynor <ckaynor@zindagigames.com> - 2013-10-22 10:35 -0700
                Re: Python Front-end to GCC Neil Cerutti <neilc@norwich.edu> - 2013-10-22 17:37 +0000
                Re: Python Front-end to GCC Oscar Benjamin <oscar.j.benjamin@gmail.com> - 2013-10-22 18:37 +0100
                Re: Python Front-end to GCC MRAB <python@mrabarnett.plus.com> - 2013-10-22 18:42 +0100
                Re: Python Front-end to GCC Grant Edwards <invalid@invalid.invalid> - 2013-10-22 18:49 +0000
                Re: Python Front-end to GCC Mark Lawrence <breamoreboy@yahoo.co.uk> - 2013-10-25 04:40 +0100
                Re: Python Front-end to GCC Mark Janssen <dreamingforward@gmail.com> - 2013-10-25 04:55 -0700
                Re: Python Front-end to GCC Dan Sommers <dan@tombstonezero.net> - 2013-10-25 12:55 +0000
                Re: Python Front-end to GCC Mark Lawrence <breamoreboy@yahoo.co.uk> - 2013-10-25 15:18 +0100
                Re: Python Front-end to GCC Ned Batchelder <ned@nedbatchelder.com> - 2013-10-25 10:35 -0400
                Re: Python Front-end to GCC Mark Janssen <dreamingforward@gmail.com> - 2013-10-25 11:26 -0700
                Re: Python Front-end to GCC Grant Edwards <invalid@invalid.invalid> - 2013-10-25 19:06 +0000
                Re: Python Front-end to GCC Mark Lawrence <breamoreboy@yahoo.co.uk> - 2013-10-25 19:40 +0100
                Re: Python Front-end to GCC Mark Janssen <dreamingforward@gmail.com> - 2013-10-25 11:45 -0700
                Re: Python Front-end to GCC rusi <rustompmody@gmail.com> - 2013-10-25 11:59 -0700
                Re: Python Front-end to GCC Mark Janssen <dreamingforward@gmail.com> - 2013-10-25 12:09 -0700
                Re: Python Front-end to GCC rusi <rustompmody@gmail.com> - 2013-10-25 12:15 -0700
                Re: Python Front-end to GCC Mark Lawrence <breamoreboy@yahoo.co.uk> - 2013-10-25 20:02 +0100
                Re: Python Front-end to GCC Mark Janssen <dreamingforward@gmail.com> - 2013-10-25 12:18 -0700
                Re: Python Front-end to GCC John Nagle <nagle@animats.com> - 2013-10-26 14:31 -0700
                Re: Python Front-end to GCC Mark Janssen <dreamingforward@gmail.com> - 2013-10-26 15:10 -0700
                Re: Python Front-end to GCC Mark Janssen <dreamingforward@gmail.com> - 2013-10-27 15:14 -0700
                Re: Python Front-end to GCC rusi <rustompmody@gmail.com> - 2013-10-27 19:15 -0700
                Re: Python Front-end to GCC Mark Lawrence <breamoreboy@yahoo.co.uk> - 2013-10-28 08:44 +0000
                Re: Python Front-end to GCC rusi <rustompmody@gmail.com> - 2013-10-28 02:31 -0700
                Re: Python Front-end to GCC Mark Lawrence <breamoreboy@yahoo.co.uk> - 2013-10-25 20:36 +0100
                Re: Python Front-end to GCC Mark Janssen <dreamingforward@gmail.com> - 2013-10-25 12:49 -0700
                Re: Python Front-end to GCC Mark Lawrence <breamoreboy@yahoo.co.uk> - 2013-10-25 21:14 +0100
                Re: Python Front-end to GCC Tim Delaney <timothy.c.delaney@gmail.com> - 2013-10-26 07:11 +1100
                Re: Python Front-end to GCC Mark Janssen <dreamingforward@gmail.com> - 2013-10-25 13:29 -0700
                Re: Python Front-end to GCC Mark Lawrence <breamoreboy@yahoo.co.uk> - 2013-10-25 21:36 +0100
                Re: Python Front-end to GCC Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2013-10-26 02:42 +0000
                Re: Python Front-end to GCC Mark Lawrence <breamoreboy@yahoo.co.uk> - 2013-10-25 21:44 +0100
                Re: Python Front-end to GCC Tim Delaney <timothy.c.delaney@gmail.com> - 2013-10-26 07:48 +1100
                Re: Python Front-end to GCC Mark Lawrence <breamoreboy@yahoo.co.uk> - 2013-10-25 21:56 +0100
                Re: Python Front-end to GCC Mark Janssen <dreamingforward@gmail.com> - 2013-10-25 14:02 -0700
                Re: Python Front-end to GCC Mark Lawrence <breamoreboy@yahoo.co.uk> - 2013-10-25 22:11 +0100
                Re: Python Front-end to GCC Mark Janssen <dreamingforward@gmail.com> - 2013-10-25 14:37 -0700
                Re: Python Front-end to GCC Mark Lawrence <breamoreboy@yahoo.co.uk> - 2013-10-25 22:56 +0100
                Re: Python Front-end to GCC Chris Angelico <rosuav@gmail.com> - 2013-10-26 13:36 +1100
                Re: Python Front-end to GCC Neil Cerutti <neilc@norwich.edu> - 2013-10-22 17:15 +0000
                Re: Python Front-end to GCC Grant Edwards <invalid@invalid.invalid> - 2013-10-22 18:58 +0000
                Re: Python Front-end to GCC Grant Edwards <invalid@invalid.invalid> - 2013-10-22 20:26 +0000
                Re: Python Front-end to GCC Grant Edwards <invalid@invalid.invalid> - 2013-10-22 15:36 +0000
              Re: Python Front-end to GCC Oscar Benjamin <oscar.j.benjamin@gmail.com> - 2013-10-22 15:15 +0100
      Re: Python Front-end to GCC Mark Janssen <dreamingforward@gmail.com> - 2013-10-21 13:14 -0700
      Re: Python Front-end to GCC Ned Batchelder <ned@nedbatchelder.com> - 2013-10-21 16:29 -0400
        Re: Python Front-end to GCC rusi <rustompmody@gmail.com> - 2013-10-21 20:40 -0700
  Re: Python Front-end to GCC Philip Herron <herron.philip@googlemail.com> - 2013-10-21 04:08 -0700
    Re: Python Front-end to GCC Mark Janssen <dreamingforward@gmail.com> - 2013-10-21 13:26 -0700
      Re: Python Front-end to GCC Philip Herron <herron.philip@googlemail.com> - 2013-10-21 14:03 -0700
        Re: Python Front-end to GCC Mark Janssen <dreamingforward@gmail.com> - 2013-10-21 16:04 -0700
          Re: Python Front-end to GCC Piet van Oostrum <piet@vanoostrum.org> - 2013-10-21 23:45 -0400
            Re: Python Front-end to GCC Mark Janssen <dreamingforward@gmail.com> - 2013-10-21 21:24 -0700
              Re: Python Front-end to GCC Steven D'Aprano <steve@pearwood.info> - 2013-10-22 05:25 +0000
            Re: Python Front-end to GCC Dave Angel <davea@davea.name> - 2013-10-22 04:39 +0000
            Re: Python Front-end to GCC Mark Janssen <dreamingforward@gmail.com> - 2013-10-22 08:04 -0700
              Re: Python Front-end to GCC Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2013-10-22 17:09 +0000
              Re: Python Front-end to GCC Piet van Oostrum <piet@vanoostrum.org> - 2013-10-22 13:20 -0400
            Re: Python Front-end to GCC Ned Batchelder <ned@nedbatchelder.com> - 2013-10-22 11:46 -0400
            Re: Python Front-end to GCC Mark Lawrence <breamoreboy@yahoo.co.uk> - 2013-10-22 16:52 +0100
            Re: Python Front-end to GCC Benjamin Kaplan <benjamin.kaplan@case.edu> - 2013-10-22 09:03 -0700
            Re: Python Front-end to GCC Mark Janssen <dreamingforward@gmail.com> - 2013-10-22 10:50 -0700
              Re: Python Front-end to GCC rusi <rustompmody@gmail.com> - 2013-10-22 11:11 -0700
              Re: Python Front-end to GCC Neil Cerutti <neilc@norwich.edu> - 2013-10-22 18:18 +0000
                Re: Python Front-end to GCC Piet van Oostrum <piet@vanoostrum.org> - 2013-10-22 15:20 -0400
                Re: Python Front-end to GCC Neil Cerutti <neilc@norwich.edu> - 2013-10-22 19:27 +0000
                Re: Python Front-end to GCC Mark Lawrence <breamoreboy@yahoo.co.uk> - 2013-10-22 20:38 +0100
                Re: Python Front-end to GCC Neil Cerutti <neilc@norwich.edu> - 2013-10-22 20:00 +0000
                Re: Python Front-end to GCC Mark Lawrence <breamoreboy@yahoo.co.uk> - 2013-10-22 20:32 +0100
            Re: Python Front-end to GCC Skip Montanaro <skip@pobox.com> - 2013-10-22 13:08 -0500
            Re: Python Front-end to GCC MRAB <python@mrabarnett.plus.com> - 2013-10-22 19:16 +0100
            Re: Python Front-end to GCC Mark Janssen <dreamingforward@gmail.com> - 2013-10-22 11:16 -0700
            Re: Python Front-end to GCC Mark Janssen <dreamingforward@gmail.com> - 2013-10-22 11:22 -0700
            Re: Python Front-end to GCC Mark Janssen <dreamingforward@gmail.com> - 2013-10-22 11:28 -0700
              Re: Python Front-end to GCC Piet van Oostrum <piet@vanoostrum.org> - 2013-10-22 18:11 -0400
                Re: Python Front-end to GCC Chris Angelico <rosuav@gmail.com> - 2013-10-23 17:28 +1100
              Re: Python Front-end to GCC Grant Edwards <invalid@invalid.invalid> - 2013-10-22 22:47 +0000
            Re: Python Front-end to GCC Ned Batchelder <ned@nedbatchelder.com> - 2013-10-22 14:23 -0400
              Re: Python Front-end to GCC rusi <rustompmody@gmail.com> - 2013-10-22 11:40 -0700
                Re: Python Front-end to GCC Mark Lawrence <breamoreboy@yahoo.co.uk> - 2013-10-22 19:58 +0100
            Re: Python Front-end to GCC Ned Batchelder <ned@nedbatchelder.com> - 2013-10-22 14:40 -0400
              Re: Python Front-end to GCC alex23 <wuwei23@gmail.com> - 2013-10-23 11:36 +1000
                Re: Python Front-end to GCC rusi <rustompmody@gmail.com> - 2013-10-22 21:04 -0700
                Re: Python Front-end to GCC Mark Lawrence <breamoreboy@yahoo.co.uk> - 2013-10-23 07:06 +0100
            Re: Python Front-end to GCC MRAB <python@mrabarnett.plus.com> - 2013-10-22 19:47 +0100
            Re: Python Front-end to GCC Ned Batchelder <ned@nedbatchelder.com> - 2013-10-22 13:56 -0400
            Re: Python Front-end to GCC Michael Torrie <torriem@gmail.com> - 2013-10-22 22:05 -0600
            Re: Python Front-end to GCC Mark Lawrence <breamoreboy@yahoo.co.uk> - 2013-10-23 07:13 +0100
            Re: Python Front-end to GCC Mark Janssen <dreamingforward@gmail.com> - 2013-10-26 14:25 -0700
            Re: Python Front-end to GCC Mark Janssen <dreamingforward@gmail.com> - 2013-10-26 14:33 -0700
            Re: Python Front-end to GCC Mark Lawrence <breamoreboy@yahoo.co.uk> - 2013-10-26 22:38 +0100
            Re: Python Front-end to GCC Mark Lawrence <breamoreboy@yahoo.co.uk> - 2013-10-26 22:35 +0100
    Re: Python Front-end to GCC Antoine Pitrou <solipsis@pitrou.net> - 2013-10-22 08:55 +0000
      Re: Python Front-end to GCC Philip Herron <herron.philip@googlemail.com> - 2013-10-22 02:08 -0700
      Re: Python Front-end to GCC Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2013-10-22 10:10 +0000
        Re: Python Front-end to GCC Antoine Pitrou <solipsis@pitrou.net> - 2013-10-22 15:51 +0000
    Re: Python Front-end to GCC Stefan Behnel <stefan_ml@behnel.de> - 2013-10-24 08:47 +0200
  Re: Python Front-end to GCC xDog Walker <thudfoo@gmail.com> - 2013-10-25 14:49 -0700

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