Re: Rationale for base class pure virtual function call from ctor/dtor being undefined behaviour.

From	"MikeWhy" <boat042-nospam@yahoo.com>
Newsgroups	comp.lang.c++
Subject	Re: Rationale for base class pure virtual function call from ctor/dtor being undefined behaviour.
Date	2012-01-17 12:14 -0600
Organization	A noiseless patient Spider
Message-ID	<jf4dpl$3eq$1@dont-email.me> (permalink)
References	(15 earlier) <S6udnZal0s2qFojSnZ2dnUVZ8uCdnZ2d@giganews.com> <c80e1e14-f27a-4b7a-946f-c91d8ddf6832@e8g2000yqd.googlegroups.com> <jf4815$26d6$1@adenine.netfront.net> <25e78f15-9c45-4464-a690-0f31d867deef@b23g2000yqn.googlegroups.com> <jf4bfv$k2b$1@dont-email.me>

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MikeWhy wrote:
> gwowen wrote:
>> On Jan 17, 4:35 pm, "Paul" <pchrist<nospam>o...@yahoo.co.uk> wrote:
>> Is [PVF] handy? Well arguably, yes, but ...
>
> The issue isn't that it is or might be useful. It is valid for a class
> method to invoke a virtual function. It is also valid for the ctor to
> call class methods, which might or might not indirectly invoke a
> virtual method. The compiler can't enforce that the ctor cannot
> indirectly invoke a virtual, pure or otherwise.
>
> Arguably, then, the PVF with implementation is not really useful, but
> simply serves as an escape for defining a benign default action during
> construction. The alternative is to always hit the UB behavior on
> invoking a PVF. On both g++ and MSVC, the result is abrupt
> termination.

(FWIW, I think the better action is to fix the object model when you 
encounter a PVF termination, rather than hide it (forever more) behind the a 
default PVF implementation.)

Thread

Rationale for base class pure virtual function call from ctor/dtor being undefined behaviour. Leigh Johnston <leigh@i42.co.uk> - 2012-01-14 23:06 +0000
  Re: Rationale for base class pure virtual function call from ctor/dtor being undefined behaviour. Goran <goran.pusic@gmail.com> - 2012-01-14 22:21 -0800
  Re: Rationale for base class pure virtual function call from ctor/dtor being undefined behaviour. "MikeWhy" <boat042-nospam@yahoo.com> - 2012-01-15 02:25 -0600
    Re: Rationale for base class pure virtual function call from ctor/dtor being undefined behaviour. Leigh Johnston <leigh@i42.co.uk> - 2012-01-15 14:07 +0000
      Re: Rationale for base class pure virtual function call from ctor/dtor being undefined behaviour. "MikeWhy" <boat042-nospam@yahoo.com> - 2012-01-15 13:13 -0600
  Re: Rationale for base class pure virtual function call from ctor/dtor being undefined behaviour. "Alf P. Steinbach" <alf.p.steinbach+usenet@gmail.com> - 2012-01-15 09:29 +0100
    Re: Rationale for base class pure virtual function call from ctor/dtor being undefined behaviour. Leigh Johnston <leigh@i42.co.uk> - 2012-01-15 14:16 +0000
      Re: Rationale for base class pure virtual function call from ctor/dtor being undefined behaviour. "Alf P. Steinbach" <alf.p.steinbach+usenet@gmail.com> - 2012-01-15 15:25 +0100
        Re: Rationale for base class pure virtual function call from ctor/dtor being undefined behaviour. Leigh Johnston <leigh@i42.co.uk> - 2012-01-15 14:30 +0000
  Re: Rationale for base class pure virtual function call from ctor/dtor being undefined behaviour. gwowen <gwowen@gmail.com> - 2012-01-16 01:57 -0800
    Re: Rationale for base class pure virtual function call from ctor/dtor being undefined behaviour. "Alf P. Steinbach" <alf.p.steinbach+usenet@gmail.com> - 2012-01-16 11:28 +0100
      Re: Rationale for base class pure virtual function call from ctor/dtor being undefined behaviour. Leigh Johnston <leigh@i42.co.uk> - 2012-01-16 11:29 +0000
      Re: Rationale for base class pure virtual function call from ctor/dtor being undefined behaviour. gwowen <gwowen@gmail.com> - 2012-01-16 03:21 -0800
  Re: Rationale for base class pure virtual function call from ctor/dtor being undefined behaviour. "Paul" <pchrist<nospam>or@yahoo.co.uk> - 2012-01-16 12:04 +0000
    Re: Rationale for base class pure virtual function call from ctor/dtor being undefined behaviour. Leigh Johnston <leigh@i42.co.uk> - 2012-01-16 12:52 +0000
      Re: Rationale for base class pure virtual function call from ctor/dtor being undefined behaviour. "Paul" <pchrist<nospam>or@yahoo.co.uk> - 2012-01-16 14:14 +0000
        Re: Rationale for base class pure virtual function call from ctor/dtor being undefined behaviour. Leigh Johnston <leigh@i42.co.uk> - 2012-01-16 14:26 +0000
          Re: Rationale for base class pure virtual function call from ctor/dtor being undefined behaviour. "Paul" <pchrist<nospam>or@yahoo.co.uk> - 2012-01-16 16:14 +0000
            Re: Rationale for base class pure virtual function call from ctor/dtor being undefined behaviour. Leigh Johnston <leigh@i42.co.uk> - 2012-01-16 16:37 +0000
              Re: Rationale for base class pure virtual function call from ctor/dtor being undefined behaviour. "Paul" <pchrist<nospam>or@yahoo.co.uk> - 2012-01-16 18:02 +0000
                Re: Rationale for base class pure virtual function call from ctor/dtor being undefined behaviour. Leigh Johnston <leigh@i42.co.uk> - 2012-01-16 18:22 +0000
                Re: Rationale for base class pure virtual function call from ctor/dtor being undefined behaviour. "Paul" <pchrist<nospam>or@yahoo.co.uk> - 2012-01-16 19:15 +0000
                Re: Rationale for base class pure virtual function call from ctor/dtor being undefined behaviour. Leigh Johnston <leigh@i42.co.uk> - 2012-01-16 20:34 +0000
                Re: Rationale for base class pure virtual function call from ctor/dtor being undefined behaviour. Leigh Johnston <leigh@i42.co.uk> - 2012-01-16 20:41 +0000
                Re: Rationale for base class pure virtual function call from ctor/dtor being undefined behaviour. "Paul" <pchrist<nospam>or@yahoo.co.uk> - 2012-01-16 20:49 +0000
                Re: Rationale for base class pure virtual function call from ctor/dtor being undefined behaviour. Leigh Johnston <leigh@i42.co.uk> - 2012-01-16 21:08 +0000
                Re: Rationale for base class pure virtual function call from ctor/dtor being undefined behaviour. Leigh Johnston <leigh@i42.co.uk> - 2012-01-16 21:11 +0000
                Re: Rationale for base class pure virtual function call from ctor/dtor being undefined behaviour. "Paul" <pchrist<nospam>or@yahoo.co.uk> - 2012-01-16 23:18 +0000
                Re: Rationale for base class pure virtual function call from ctor/dtor being undefined behaviour. Leigh Johnston <leigh@i42.co.uk> - 2012-01-16 23:39 +0000
                Re: Rationale for base class pure virtual function call from ctor/dtor being undefined behaviour. "Paul" <pchrist<nospam>or@yahoo.co.uk> - 2012-01-16 23:48 +0000
                Re: Rationale for base class pure virtual function call from ctor/dtor being undefined behaviour. Leigh Johnston <leigh@i42.co.uk> - 2012-01-16 23:57 +0000
                Re: Rationale for base class pure virtual function call from ctor/dtor being undefined behaviour. "Paul" <pchrist<nospam>or@yahoo.co.uk> - 2012-01-17 12:24 +0000
                Re: Rationale for base class pure virtual function call from ctor/dtor being undefined behaviour. Leigh Johnston <leigh@i42.co.uk> - 2012-01-17 14:11 +0000
                Re: Rationale for base class pure virtual function call from ctor/dtor being undefined behaviour. gwowen <gwowen@gmail.com> - 2012-01-17 06:43 -0800
                Re: Rationale for base class pure virtual function call from ctor/dtor being undefined behaviour. Leigh Johnston <leigh@i42.co.uk> - 2012-01-17 14:52 +0000
                Re: Rationale for base class pure virtual function call from ctor/dtor being undefined behaviour. gwowen <gwowen@gmail.com> - 2012-01-17 07:22 -0800
                Re: Rationale for base class pure virtual function call from ctor/dtor being undefined behaviour. "Paul" <pchrist<nospam>or@yahoo.co.uk> - 2012-01-17 16:35 +0000
                Re: Rationale for base class pure virtual function call from ctor/dtor being undefined behaviour. Leigh Johnston <leigh@i42.co.uk> - 2012-01-17 16:40 +0000
                Re: Rationale for base class pure virtual function call from ctor/dtor being undefined behaviour. "Paul" <pchrist<nospam>or@yahoo.co.uk> - 2012-01-17 17:30 +0000
                Re: Rationale for base class pure virtual function call from ctor/dtor being undefined behaviour. "Paul" <pchrist<nospam>or@yahoo.co.uk> - 2012-01-18 10:38 +0000
                Re: Rationale for base class pure virtual function call from ctor/dtor being undefined behaviour. Leigh Johnston <leigh@i42.co.uk> - 2012-01-18 11:57 +0000
                Re: Rationale for base class pure virtual function call from ctor/dtor being undefined behaviour. "Paul" <pchrist<nospam>or@yahoo.co.uk> - 2012-01-18 12:49 +0000
                Re: Rationale for base class pure virtual function call from ctor/dtor being undefined behaviour. gwowen <gwowen@gmail.com> - 2012-01-17 08:59 -0800
                Re: Rationale for base class pure virtual function call from ctor/dtor being undefined behaviour. Leigh Johnston <leigh@i42.co.uk> - 2012-01-17 17:03 +0000
                Re: Rationale for base class pure virtual function call from ctor/dtor being undefined behaviour. "MikeWhy" <boat042-nospam@yahoo.com> - 2012-01-17 11:34 -0600
                Re: Rationale for base class pure virtual function call from ctor/dtor being undefined behaviour. "MikeWhy" <boat042-nospam@yahoo.com> - 2012-01-17 12:14 -0600
                Re: Rationale for base class pure virtual function call from ctor/dtor being undefined behaviour. Gareth Owen <gwowen@gmail.com> - 2012-01-18 06:37 +0000
                Re: Rationale for base class pure virtual function call from ctor/dtor being undefined behaviour. "MikeWhy" <boat042-nospam@yahoo.com> - 2012-01-18 13:08 -0600
                Re: Rationale for base class pure virtual function call from ctor/dtor being undefined behaviour. "MikeWhy" <boat042-nospam@yahoo.com> - 2012-01-18 13:14 -0600
                Re: Rationale for base class pure virtual function call from ctor/dtor being undefined behaviour. "Paul" <pchrist<nospam>or@yahoo.co.uk> - 2012-01-17 15:50 +0000
                Re: Rationale for base class pure virtual function call from ctor/dtor being undefined behaviour. Leigh Johnston <leigh@i42.co.uk> - 2012-01-17 15:59 +0000
                Re: Rationale for base class pure virtual function call from ctor/dtor being undefined behaviour. "Paul" <pchrist<nospam>or@yahoo.co.uk> - 2012-01-17 16:09 +0000
          Re: Rationale for base class pure virtual function call from ctor/dtor being undefined behaviour. jgk@panix.com (Joe keane) - 2012-01-17 16:13 +0000
            Re: Rationale for base class pure virtual function call from ctor/dtor being undefined behaviour. scott@slp53.sl.home (Scott Lurndal) - 2012-01-18 18:11 +0000
        Re: Rationale for base class pure virtual function call from ctor/dtor being undefined behaviour. gwowen <gwowen@gmail.com> - 2012-01-16 06:34 -0800
  Re: Rationale for base class pure virtual function call from ctor/dtor being undefined behaviour. Gil <vnicula@gmail.com> - 2012-01-16 20:55 -0800
  Re: Rationale for base class pure virtual function call from ctor/dtor being undefined behaviour. Leigh Johnston <leigh@i42.co.uk> - 2012-01-17 17:58 +0000
    Re: Rationale for base class pure virtual function call from ctor/dtor being undefined behaviour. scott@slp53.sl.home (Scott Lurndal) - 2012-01-18 18:12 +0000
      Re: Rationale for base class pure virtual function call from ctor/dtor being undefined behaviour. Leigh Johnston <leigh@i42.co.uk> - 2012-01-18 19:00 +0000
        Re: Rationale for base class pure virtual function call from ctor/dtor being undefined behaviour. "Paul" <pchrist<nospam>or@yahoo.co.uk> - 2012-01-18 22:00 +0000
      Re: Rationale for base class pure virtual function call from ctor/dtor being undefined behaviour. Gareth Owen <gwowen@gmail.com> - 2012-01-19 06:22 +0000

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