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Re: Fun with member-function pointers

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On 8/24/2011 9:15 AM, Default User wrote:
>
>> Again, beware of broken compilers that might not handle it correctly. But
>> for your specific example I don't expect any surprises from the compiler.
>
> VS 2010 builds the example without complaint. Results are what I would want.

Well, VS is actually the problematic one. It has a bunch of settings 
(see '/vms', '/vmm' and '/vmv') intended to control the trade-off 
between compiler compliance and member-function-pointer size/simplicity 
in this specific kind of situation (depending on the inheritance model).

However, somehow they managed to let the Marcel's example slip through. 
When the VMT pointer is introduced into the class layout late in the 
hierarchy (i.e. the base class is not polymorphic, while the derived 
class is), the compiler fails to produce correct code. It is especially 
strange in light of the fact that all the infrastructure that is needed 
to handle this situation correctly is already built into the compiler 
(layout change is similar to that caused by ordinary multiple 
inheritance). Yet that managed to screw this specific case up. It is 
broken in VS 2005. It remains broken is VS 2010.

Of course, one can work around this issue fairly easily by moving the 
VMT pointer all the way up the hierarchy, i.e. by forcefully making the 
base class polymorphic (not even mentioning that it will already be the 
case in [almost] all practical designs). Nevertheless, it is important 
to be aware of it.

-- 
Best regards,
Andrey Tarasevich

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Thread

Fun with member-function pointers "Default User" <defaultuserbr@yahoo.com> - 2011-08-22 16:41 -0500
  Re: Fun with member-function pointers Victor Bazarov <v.bazarov@comcast.invalid> - 2011-08-22 19:25 -0400
    Re: Fun with member-function pointers "Default User" <defaultuserbr@yahoo.com> - 2011-08-22 19:06 -0500
  Re: Fun with member-function pointers Juha Nieminen <nospam@thanks.invalid> - 2011-08-23 07:09 +0000
    Re: Fun with member-function pointers Victor Bazarov <v.bazarov@comcast.invalid> - 2011-08-23 08:04 -0400
      Re: Fun with member-function pointers Juha Nieminen <nospam@thanks.invalid> - 2011-08-23 13:34 +0000
        Re: Fun with member-function pointers Victor Bazarov <v.bazarov@comcast.invalid> - 2011-08-23 13:02 -0400
      Re: Fun with member-function pointers Andrey Tarasevich <andreytarasevich@hotmail.com> - 2011-08-23 19:12 -0700
    Re: Fun with member-function pointers Andrey Tarasevich <andreytarasevich@hotmail.com> - 2011-08-23 18:51 -0700
  Re: Fun with member-function pointers Marcel Müller <news.5.maazl@spamgourmet.com> - 2011-08-23 09:07 +0200
    Re: Fun with member-function pointers Juha Nieminen <nospam@thanks.invalid> - 2011-08-23 10:09 +0000
      Re: Fun with member-function pointers Marcel Müller <news.5.maazl@spamgourmet.com> - 2011-08-23 15:04 +0200
    Re: Fun with member-function pointers "Default User" <defaultuserbr@yahoo.com> - 2011-08-23 10:36 -0500
      Re: Fun with member-function pointers Andrey Tarasevich <andreytarasevich@hotmail.com> - 2011-08-23 18:46 -0700
        Re: Fun with member-function pointers "Default User" <defaultuserbr@yahoo.com> - 2011-08-24 09:33 -0500
          Re: Fun with member-function pointers Andrey Tarasevich <andreytarasevich@hotmail.com> - 2011-08-24 08:32 -0700
            Re: Fun with member-function pointers "Default User" <defaultuserbr@yahoo.com> - 2011-08-24 11:15 -0500
              Re: Fun with member-function pointers Andrey Tarasevich <andreytarasevich@hotmail.com> - 2011-08-24 09:30 -0700
      Re: Fun with member-function pointers Marcel Müller <news.5.maazl@spamgourmet.com> - 2011-08-24 12:27 +0200
        Re: Fun with member-function pointers Andrey Tarasevich <andreytarasevich@hotmail.com> - 2011-08-24 06:46 -0700
          Re: Fun with member-function pointers Marcel Müller <news.5.maazl@spamgourmet.org> - 2011-08-24 18:57 +0200
            Re: Fun with member-function pointers Paul <pchristor@yahoo.co.uk> - 2011-08-24 13:08 -0700
              Re: Fun with member-function pointers Andrey Tarasevich <andreytarasevich@hotmail.com> - 2011-08-24 13:44 -0700
                Re: Fun with member-function pointers Paul <pchristor@yahoo.co.uk> - 2011-08-25 04:23 -0700
                Re: Fun with member-function pointers Andrey Tarasevich <andreytarasevich@hotmail.com> - 2011-08-25 07:31 -0700
                Re: Fun with member-function pointers Andrey Tarasevich <andreytarasevich@hotmail.com> - 2011-08-25 08:21 -0700
                Re: Fun with member-function pointers Paul <pchristor@yahoo.co.uk> - 2011-08-25 10:50 -0700
                Re: Fun with member-function pointers Leigh Johnston <leigh@i42.co.uk> - 2011-08-25 13:57 +0100
                Re: Fun with member-function pointers Leigh Johnston <leigh@i42.co.uk> - 2011-08-25 14:08 +0100
                Re: Fun with member-function pointers Andrey Tarasevich <andreytarasevich@hotmail.com> - 2011-08-25 07:32 -0700
                Re: Fun with member-function pointers Leigh Johnston <leigh@i42.co.uk> - 2011-08-25 15:45 +0100
                Re: Fun with member-function pointers Andrey Tarasevich <andreytarasevich@hotmail.com> - 2011-08-25 07:48 -0700
    Re: Fun with member-function pointers Andrey Tarasevich <andreytarasevich@hotmail.com> - 2011-08-23 18:43 -0700
  Re: Fun with member-function pointers Paul <pchristor@yahoo.co.uk> - 2011-08-23 03:49 -0700
    Re: Fun with member-function pointers Paul <pchristor@yahoo.co.uk> - 2011-08-23 06:44 -0700
  Re: Fun with member-function pointers Andrey Tarasevich <andreytarasevich@hotmail.com> - 2011-08-23 18:28 -0700
  Re: Fun with member-function pointers Jeff Flinn <TriumphSprint2000@hotmail.com> - 2011-08-25 11:29 -0400

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