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Re: noob question - destructors - freeing memory...

From "Bo Persson" <bop@gmb.dk>
Newsgroups comp.lang.c++
Subject Re: noob question - destructors - freeing memory...
Date 2011-12-31 12:55 +0100
Message-ID <9m8bi2FrgvU1@mid.individual.net> (permalink)
References <jdlpc1$cdi$1@dont-email.me> <jdlqo9$i9j$1@dont-email.me> <4efe7460$0$293$14726298@news.sunsite.dk>

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someone wrote:
> On 12/31/2011 03:06 AM, MikeWhy wrote:
>>
>> If pointers had destructors, what action should they take?
>
> Delete themselves? But not before they've destructed the objects
> they're pointing to! After they've destructed (free'd) the
> dereferenced objects, the pointers can free themselves...
>
> Why doesn't that happen in the example in my post and in my full
> code?

There are several reasons. One is that pointers are inherited from the 
C language, and are expected to behave the same as they did there. In 
C there are no destructors at all.

Another reason is that there can be several pointers pointing to the 
same object. How are they supposed to know which one should delete the 
object pointed to? Or if anyone should do that. Not all pointed-to 
objects are created by new.

{
    int i = 0;
    int* p = &i;
}

Here we should definitely *not* call delete p.


Bo Persson

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Thread

noob question - destructors - freeing memory... someone <newsboost@gmail.com> - 2011-12-31 02:43 +0100
  Re: noob question - destructors - freeing memory... "MikeWhy" <boat042-nospam@yahoo.com> - 2011-12-30 20:06 -0600
    Re: noob question - destructors - freeing memory... someone <newsboost@gmail.com> - 2011-12-31 03:33 +0100
      Re: noob question - destructors - freeing memory... "MikeWhy" <boat042-nospam@yahoo.com> - 2011-12-30 21:22 -0600
        Re: noob question - destructors - freeing memory... someone <newsboost@gmail.com> - 2011-12-31 04:57 +0100
          Re: noob question - destructors - freeing memory... "MikeWhy" <boat042-nospam@yahoo.com> - 2011-12-30 22:28 -0600
            Re: noob question - destructors - freeing memory... "MikeWhy" <boat042-nospam@yahoo.com> - 2011-12-30 22:43 -0600
            Re: noob question - destructors - freeing memory... someone <newsboost@gmail.com> - 2011-12-31 05:49 +0100
              Re: noob question - destructors - freeing memory... "MikeWhy" <boat042-nospam@yahoo.com> - 2011-12-30 23:56 -0600
                Re: noob question - destructors - freeing memory... someone <newsboost@gmail.com> - 2011-12-31 07:07 +0100
                Re: noob question - destructors - freeing memory... Nick Keighley <nick_keighley_nospam@hotmail.com> - 2011-12-31 01:50 -0800
                Re: noob question - destructors - freeing memory... someone <newsboost@gmail.com> - 2011-12-31 18:13 +0100
                Re: noob question - destructors - freeing memory... Nobody <nobody@nowhere.com> - 2012-01-01 08:37 +0000
                Re: noob question - destructors - freeing memory... LR <lruss@superlink.net> - 2012-01-01 10:54 -0500
                Re: noob question - destructors - freeing memory... someone <newsboost@gmail.com> - 2012-01-02 00:33 +0100
                Re: noob question - destructors - freeing memory... "MikeWhy" <boat042-nospam@yahoo.com> - 2012-01-01 19:20 -0600
                Re: noob question - destructors - freeing memory... someone <newsboost@gmail.com> - 2012-01-02 03:55 +0100
                Re: noob question - destructors - freeing memory... Stefan Ensslen <stefan@zollsoft.de> - 2012-01-02 04:32 -0800
                Re: noob question - destructors - freeing memory... someone <newsboost@gmail.com> - 2012-01-02 17:40 +0100
                Re: noob question - destructors - freeing memory... Dombo <dombo@disposable.invalid> - 2012-01-02 19:14 +0100
                Re: noob question - destructors - freeing memory... someone <newsboost@gmail.com> - 2012-01-02 21:30 +0100
                Re: noob question - destructors - freeing memory... jgk@panix.com (Joe keane) - 2012-01-07 23:23 +0000
                Re: noob question - destructors - freeing memory... "MikeWhy" <boat042-nospam@yahoo.com> - 2012-01-07 17:43 -0600
                Re: noob question - destructors - freeing memory... Garrett Hartshaw <ghartshaw@gmail.com> - 2012-01-01 22:54 -0500
                Re: noob question - destructors - freeing memory... someone <newsboost@gmail.com> - 2012-01-02 05:29 +0100
                Re: noob question - destructors - freeing memory... Nick Keighley <nick_keighley_nospam@hotmail.com> - 2012-01-01 13:38 -0800
                Re: noob question - destructors - freeing memory... someone <newsboost@gmail.com> - 2012-01-02 00:35 +0100
      Re: noob question - destructors - freeing memory... "Bo Persson" <bop@gmb.dk> - 2011-12-31 12:55 +0100
  Re: noob question - destructors - freeing memory... Garrett Hartshaw <ghartshaw@gmail.com> - 2011-12-30 22:50 -0500
    Re: noob question - destructors - freeing memory... someone <newsboost@gmail.com> - 2011-12-31 05:37 +0100
      Re: noob question - destructors - freeing memory... LR <lruss@superlink.net> - 2011-12-31 01:07 -0500
        Re: noob question - destructors - freeing memory... someone <newsboost@gmail.com> - 2011-12-31 08:54 +0100
          Re: noob question - destructors - freeing memory... Nick Keighley <nick_keighley_nospam@hotmail.com> - 2011-12-31 02:05 -0800
            Re: noob question - destructors - freeing memory... someone <newsboost@gmail.com> - 2011-12-31 18:22 +0100
              Re: noob question - destructors - freeing memory... Nick Keighley <nick_keighley_nospam@hotmail.com> - 2012-01-01 13:45 -0800
                Re: noob question - destructors - freeing memory... Jorgen Grahn <grahn+nntp@snipabacken.se> - 2012-01-02 12:17 +0000
                Re: noob question - destructors - freeing memory... someone <newsboost@gmail.com> - 2012-01-02 17:48 +0100
                Re: noob question - destructors - freeing memory... Jorgen Grahn <grahn+nntp@snipabacken.se> - 2012-01-02 20:02 +0000
              Re: noob question - destructors - freeing memory... Nick Keighley <nick_keighley_nospam@hotmail.com> - 2012-01-01 13:42 -0800
      Re: noob question - destructors - freeing memory... Nick Keighley <nick_keighley_nospam@hotmail.com> - 2011-12-31 01:52 -0800
        Re: noob question - destructors - freeing memory... someone <newsboost@gmail.com> - 2011-12-31 18:23 +0100
      Re: noob question - destructors - freeing memory... Garrett Hartshaw <ghartshaw@gmail.com> - 2011-12-31 12:35 -0500
        Re: noob question - destructors - freeing memory... someone <newsboost@gmail.com> - 2012-01-02 00:47 +0100
  Re: noob question - destructors - freeing memory... Juha Nieminen <nospam@thanks.invalid> - 2011-12-31 09:40 +0000
    Re: noob question - destructors - freeing memory... someone <newsboost@gmail.com> - 2011-12-31 18:26 +0100
      Re: noob question - destructors - freeing memory... Garrett Hartshaw <ghartshaw@gmail.com> - 2011-12-31 13:00 -0500
      Re: noob question - destructors - freeing memory... Nobody <nobody@nowhere.com> - 2012-01-01 08:57 +0000
        Re: noob question - destructors - freeing memory... someone <newsboost@gmail.com> - 2012-01-02 00:43 +0100
      Re: noob question - destructors - freeing memory... Juha Nieminen <nospam@thanks.invalid> - 2012-01-01 09:03 +0000
        Re: noob question - destructors - freeing memory... someone <newsboost@gmail.com> - 2012-01-02 00:49 +0100
          Re: noob question - destructors - freeing memory... LR <lruss@superlink.net> - 2012-01-01 21:11 -0500
            Re: noob question - destructors - freeing memory... POSSIBLE SOLUTION FOUND? someone <newsboost@gmail.com> - 2012-01-02 05:23 +0100
              Re: noob question - destructors - freeing memory... POSSIBLE SOLUTION
 FOUND? Garrett Hartshaw <ghartshaw@gmail.com> - 2012-01-02 00:14 -0500
                Re: noob question - destructors - freeing memory... POSSIBLE SOLUTION FOUND? someone <newsboost@gmail.com> - 2012-01-02 17:55 +0100
                Re: noob question - destructors - freeing memory... POSSIBLE SOLUTION FOUND? someone <newsboost@gmail.com> - 2012-01-02 22:17 +0100
                Re: noob question - destructors - freeing memory... POSSIBLE SOLUTION
 FOUND? Garrett Hartshaw <ghartshaw@gmail.com> - 2012-01-02 16:40 -0500
                Re: noob question - destructors - freeing memory... POSSIBLE SOLUTION FOUND? someone <newsboost@gmail.com> - 2012-01-03 00:48 +0100
              Re: noob question - destructors - freeing memory... POSSIBLE SOLUTION FOUND? LR <lruss@superlink.net> - 2012-01-02 14:47 -0500
                Re: noob question - destructors - freeing memory... POSSIBLE SOLUTION FOUND? someone <newsboost@gmail.com> - 2012-01-03 00:43 +0100
                Re: noob question - destructors - freeing memory... POSSIBLE SOLUTION FOUND? LR <lruss@superlink.net> - 2012-01-02 20:30 -0500
                Re: noob question - destructors - freeing memory... POSSIBLE SOLUTION FOUND? someone <newsboost@gmail.com> - 2012-01-03 19:08 +0100
                Re: noob question - destructors - freeing memory... POSSIBLE SOLUTION FOUND? LR <lruss@superlink.net> - 2012-01-03 17:46 -0500
                Re: noob question - destructors - freeing memory... POSSIBLE SOLUTION FOUND? someone <newsboost@gmail.com> - 2012-01-04 21:11 +0100
                Re: noob question - destructors - freeing memory... POSSIBLE SOLUTION FOUND? LR <lruss@superlink.net> - 2012-01-04 18:56 -0500
                Re: noob question - destructors - freeing memory... POSSIBLE SOLUTION
 FOUND? Garrett Hartshaw <ghartshaw@gmail.com> - 2012-01-03 19:49 -0500
                Re: noob question - destructors - freeing memory... POSSIBLE SOLUTION FOUND? LR <lruss@superlink.net> - 2012-01-03 21:51 -0500
                Re: noob question - destructors - freeing memory... POSSIBLE SOLUTION
 FOUND? Garrett Hartshaw <ghartshaw@gmail.com> - 2012-01-03 23:37 -0500
                Re: noob question - destructors - freeing memory... POSSIBLE SOLUTION FOUND? LR <lruss@superlink.net> - 2012-01-04 14:24 -0500
                Re: noob question - destructors - freeing memory... POSSIBLE SOLUTION FOUND? someone <newsboost@gmail.com> - 2012-01-04 21:20 +0100
                Re: noob question - destructors - freeing memory... POSSIBLE SOLUTION FOUND? LR <lruss@superlink.net> - 2012-01-04 18:51 -0500
                Re: noob question - destructors - freeing memory... POSSIBLE SOLUTION FOUND? someone <newsboost@gmail.com> - 2012-01-05 07:32 +0100
          Re: noob question - destructors - freeing memory... Garrett Hartshaw <ghartshaw@gmail.com> - 2012-01-01 23:02 -0500
            Re: noob question - destructors - freeing memory... someone <newsboost@gmail.com> - 2012-01-02 05:33 +0100
            Re: noob question - destructors - freeing memory... "io_x" <a@b.c.invalid> - 2012-01-02 11:05 +0100
          Re: noob question - destructors - freeing memory... Juha Nieminen <nospam@thanks.invalid> - 2012-01-02 06:22 +0000
            Re: noob question - destructors - freeing memory... someone <newsboost@gmail.com> - 2012-01-02 18:03 +0100
  Re: noob question - destructors - freeing memory... "Bo Persson" <bop@gmb.dk> - 2011-12-31 12:51 +0100
    Re: noob question - destructors - freeing memory... someone <newsboost@gmail.com> - 2011-12-31 18:18 +0100

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