Re: init is the initialiser

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From	Devin Jeanpierre <jeanpierreda@gmail.com>
Date	Sun, 2 Feb 2014 17:24:21 -0800
Subject	Re: __init__ is the initialiser
To	Chris Angelico <rosuav@gmail.com>
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On Sun, Feb 2, 2014 at 4:07 PM, Chris Angelico <rosuav@gmail.com> wrote:
> On Mon, Feb 3, 2014 at 10:40 AM, Roy Smith <roy@panix.com> wrote:
>> I'm reasonably sure you posted this as humor, but there is some truth in
>> what you said.  In the crypto/security domain, you often want to keep a
>> key or cleartext around only for the time it's needed, and scrub the
>> memory it was occupying as soon as it is no longer in use.
>>
>> I don't know how you would do that in Python.
>
> I did, but you're right.
>
> It's fundamentally not possible in pure Python, because there's no way
> to flag a block of memory as "do not page this to disk". For what
> you're talking about to be at all possible, you would need support
> from the language, from the OS,

mlock on linux, VirtualAlloc (?) on windows. This can be done in
CPython after the fact, but you'd want the memory to be unpageable
before it has contents put in it, not after.

Destroying memory is comparatively easy, as you say -- just make the
object's internal state "invalid", rather than adding anything to the
language.

-- Devin

Thread

Re: __init__ is the initialiser Terry Reedy <tjreedy@udel.edu> - 2014-01-31 22:16 -0500
  Re: __init__ is the initialiser Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2014-02-01 05:23 +0000
    Re: __init__ is the initialiser Roy Smith <roy@panix.com> - 2014-02-01 00:25 -0500
      Re: __init__ is the initialiser Gregory Ewing <greg.ewing@canterbury.ac.nz> - 2014-02-03 12:15 +1300
        Re: __init__ is the initialiser Chris Angelico <rosuav@gmail.com> - 2014-02-03 10:27 +1100
          Re: __init__ is the initialiser Roy Smith <roy@panix.com> - 2014-02-02 18:40 -0500
            Re: __init__ is the initialiser Chris Angelico <rosuav@gmail.com> - 2014-02-03 11:07 +1100
            Re: __init__ is the initialiser Devin Jeanpierre <jeanpierreda@gmail.com> - 2014-02-02 17:24 -0800
            Re: __init__ is the initialiser Chris Angelico <rosuav@gmail.com> - 2014-02-03 12:37 +1100
            Re: __init__ is the initialiser Devin Jeanpierre <jeanpierreda@gmail.com> - 2014-02-02 17:54 -0800
            Re: __init__ is the initialiser Dennis Lee Bieber <wlfraed@ix.netcom.com> - 2014-02-03 08:44 -0500
            Re: __init__ is the initialiser Nicholas Cole <nicholas.cole@gmail.com> - 2014-02-03 13:50 +0000
            Re: __init__ is the initialiser Ian Kelly <ian.g.kelly@gmail.com> - 2014-02-03 10:44 -0700
            Re: __init__ is the initialiser Chris Angelico <rosuav@gmail.com> - 2014-02-04 04:57 +1100
            Re: __init__ is the initialiser Nicholas Cole <nicholas.cole@gmail.com> - 2014-02-03 19:57 +0000
            Re: __init__ is the initialiser Dennis Lee Bieber <wlfraed@ix.netcom.com> - 2014-02-03 19:38 -0500
        Re: __init__ is the initialiser Dave Angel <davea@davea.name> - 2014-02-02 19:35 -0500
          Re: __init__ is the initialiser Roy Smith <roy@panix.com> - 2014-02-02 19:45 -0500
            Re: __init__ is the initialiser Dave Angel <davea@davea.name> - 2014-02-02 22:14 -0500
            Re: __init__ is the initialiser Skip Montanaro <skip@pobox.com> - 2014-02-02 21:15 -0600
            Re: __init__ is the initialiser Dave Angel <davea@davea.name> - 2014-02-03 00:06 -0500
              Re: __init__ is the initialiser Roy Smith <roy@panix.com> - 2014-02-03 00:12 -0500
                Re: __init__ is the initialiser Chris Angelico <rosuav@gmail.com> - 2014-02-03 16:49 +1100
                Re: __init__ is the initialiser Ethan Furman <ethan@stoneleaf.us> - 2014-02-02 21:34 -0800
    Re: __init__ is the initialiser Rustom Mody <rustompmody@gmail.com> - 2014-01-31 21:31 -0800

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