Re: Is it possible to test if a raw pointer is pointing to a valid object?

From	Lynn McGuire <lynnmcguire5@gmail.com>
Newsgroups	comp.lang.c++
Subject	Re: Is it possible to test if a raw pointer is pointing to a valid object?
Date	2022-08-26 16:08 -0500
Organization	A noiseless patient Spider
Message-ID	<tebcot$2gpm$2@dont-email.me> (permalink)
References	<te5lf8$3camt$1@dont-email.me>

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On 8/24/2022 12:00 PM, JiiPee wrote:
> First the code. The question below it:
> 
> ------------------------
> class Parent
> {
> public:
>      void foo2() {}
> };
> 
> class Child
> {
> public:
>      Parent* m_parent{nullptr};
>      void foo() {
>          // can the validity of the raw pointer m_parent be checked?
>          m_parent->foo2();
>      }
> };
> 
> void main()
> {
>      Parent* parent = new Parent;
>      Child child;
>      child.m_parent = parent;
>      delete parent;
>      child.foo(); // any way this call knowing parent is now deleted?
> 
> }
> 
> ------------------
> 
> Is there any way to check if a raw pointer is pointing to a valid object?
> Because I have situations where I can only store raw pointers.
> I know it can be done with shared pointers, but how about raw pointers?
> Assuming I cannot change the Parent class in the above example.
> Or is there any pattern applied to Child class... again assuming we 
> cannot change the Parent class at all.

Yes.  You need to wrap new, realloc, malloc, and free with your own code 
and keep track of all your memory allocations.

Lynn

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Thread

Is it possible to test if a raw pointer is pointing to a valid object? JiiPee <kerrttuPoistaTama11@gmail.com> - 2022-08-24 20:00 +0300
  Re: Is it possible to test if a raw pointer is pointing to a valid object? Paavo Helde <eesnimi@osa.pri.ee> - 2022-08-24 20:24 +0300
    Re: Is it possible to test if a raw pointer is pointing to a valid object? Paavo Helde <eesnimi@osa.pri.ee> - 2022-08-24 20:28 +0300
    Re: Is it possible to test if a raw pointer is pointing to a valid object? JiiPee <kerrttuPoistaTama11@gmail.com> - 2022-08-24 20:39 +0300
    Re: Is it possible to test if a raw pointer is pointing to a valid object? Keith Thompson <Keith.S.Thompson+u@gmail.com> - 2022-08-24 10:44 -0700
      Re: Is it possible to test if a raw pointer is pointing to a valid object? JiiPee <kerrttuPoistaTama11@gmail.com> - 2022-08-24 20:51 +0300
        Re: Is it possible to test if a raw pointer is pointing to a valid object? JiiPee <kerrttuPoistaTama11@gmail.com> - 2022-08-24 20:52 +0300
          Re: Is it possible to test if a raw pointer is pointing to a valid object? Keith Thompson <Keith.S.Thompson+u@gmail.com> - 2022-08-24 11:59 -0700
            Re: Is it possible to test if a raw pointer is pointing to a valid object? Manfred <noname@add.invalid> - 2022-08-26 02:26 +0200
  Re: Is it possible to test if a raw pointer is pointing to a valid object? JiiPee <kerrttuPoistaTama11@gmail.com> - 2022-08-24 20:41 +0300
    Re: Is it possible to test if a raw pointer is pointing to a valid object? Louis Krupp <lkrupp@invalid.pssw.com.invalid> - 2022-08-24 13:51 -0600
  Re: Is it possible to test if a raw pointer is pointing to a valid object? Malcolm McLean <malcolm.arthur.mclean@gmail.com> - 2022-08-24 12:45 -0700
    Re: Is it possible to test if a raw pointer is pointing to a valid object? JiiPee <kerrttuPoistaTama11@gmail.com> - 2022-08-24 23:17 +0300
      Re: Is it possible to test if a raw pointer is pointing to a valid object? scott@slp53.sl.home (Scott Lurndal) - 2022-08-24 20:54 +0000
        Re: Is it possible to test if a raw pointer is pointing to a valid object? Malcolm McLean <malcolm.arthur.mclean@gmail.com> - 2022-08-24 14:57 -0700
          Re: Is it possible to test if a raw pointer is pointing to a valid object? Vir Campestris <vir.campestris@invalid.invalid> - 2022-08-25 12:52 +0100
  Re: Is it possible to test if a raw pointer is pointing to a valid         object? Sam <sam@email-scan.com> - 2022-08-24 20:21 -0400
  Re: Is it possible to test if a raw pointer is pointing to a valid object? Bonita Montero <Bonita.Montero@gmail.com> - 2022-08-25 07:39 +0200
    Re: Is it possible to test if a raw pointer is pointing to a valid object? Malcolm McLean <malcolm.arthur.mclean@gmail.com> - 2022-08-25 03:37 -0700
      Re: Is it possible to test if a raw pointer is pointing to a valid         object? Sam <sam@email-scan.com> - 2022-08-25 09:37 -0400
      Re: Is it possible to test if a raw pointer is pointing to a valid object? JiiPee <kerrttuPoistaTama11@gmail.com> - 2022-08-25 17:28 +0300
        Re: Is it possible to test if a raw pointer is pointing to a valid         object? Sam <sam@email-scan.com> - 2022-08-25 19:39 -0400
        Re: Is it possible to test if a raw pointer is pointing to a valid object? Paul N <gw7rib@aol.com> - 2022-08-26 05:49 -0700
          Re: Is it possible to test if a raw pointer is pointing to a valid object? JiiPee <kerrttuPoistaTama11@gmail.com> - 2022-08-26 19:35 +0300
            Re: Is it possible to test if a raw pointer is pointing to a valid object? Louis Krupp <lkrupp@invalid.pssw.com.invalid> - 2022-08-26 12:25 -0600
      Re: Is it possible to test if a raw pointer is pointing to a valid object? "Chris M. Thomasson" <chris.m.thomasson.1@gmail.com> - 2022-08-25 11:38 -0700
  Re: Is it possible to test if a raw pointer is pointing to a valid object? Lynn McGuire <lynnmcguire5@gmail.com> - 2022-08-26 16:08 -0500

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