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Re: does virtualizing all methods slow C++ down ?

From "Thomas J. Gritzan" <phygon_antispam@gmx.de>
Newsgroups comp.lang.c++
Subject Re: does virtualizing all methods slow C++ down ?
Date 2011-09-07 02:42 +0200
Organization news.netcologne.de
Message-ID <j46em4$26o$1@newsreader4.netcologne.de> (permalink)
References <j45hvi$6at$1@dont-email.me> <c19c435c-8bf2-4e31-a950-72336682ca15@q8g2000yqe.googlegroups.com>

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> On Sep 6, 11:31 am, Lynn McGuire<l...@winsim.com>  wrote:
>> Does virtualizing all methods slow C++ down ?
 >> [...]

At 06.09.2011 19:00, Christopher wrote:
> If you virtualize one, there is no cost for virtualizing the others.
> There is a cost associated with virtualizing one method. See the FAQ.

That's not true.

It is true that the size of an object increases for the first virtual 
function you add, but not for further virtual functions (for usual 
vpointer implementations).
However, _every_ function might be slower when called virtually, because 
the compiler has less potential for optimization (function inlining etc) 
than for non-virtual functions.

-- 
Thomas

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Thread

does virtualizing all methods slow C++ down ? Lynn McGuire <lmc@winsim.com> - 2011-09-06 11:31 -0500
  Re: does virtualizing all methods slow C++ down ? Christopher <cpisz@austin.rr.com> - 2011-09-06 10:00 -0700
    Re: does virtualizing all methods slow C++ down ? Lynn McGuire <lmc@winsim.com> - 2011-09-06 14:09 -0500
      Re: does virtualizing all methods slow C++ down ? Christopher <cpisz@austin.rr.com> - 2011-09-06 12:35 -0700
        Re: does virtualizing all methods slow C++ down ? "Kevin P. Fleming" <news@kpfleming.us> - 2011-09-06 16:41 -0500
      Re: does virtualizing all methods slow C++ down ? "Balog Pal" <pasa@lib.hu> - 2011-09-11 12:02 +0200
    Re: does virtualizing all methods slow C++ down ? "Thomas J. Gritzan" <phygon_antispam@gmx.de> - 2011-09-07 02:42 +0200
      Re: does virtualizing all methods slow C++ down ? Noah Roberts <roberts.noah@gmail.com> - 2011-09-07 07:39 -0700
        Re: does virtualizing all methods slow C++ down ? Richard Damon <news.x.richarddamon@xoxy.net> - 2011-09-07 11:46 -0400
    Re: does virtualizing all methods slow C++ down ? Nobody <nobody@nowhere.com> - 2011-09-07 01:45 +0100
  Re: does virtualizing all methods slow C++ down ? Alain Ketterlin <alain@dpt-info.u-strasbg.fr> - 2011-09-06 19:12 +0200
    Re: does virtualizing all methods slow C++ down ? Lynn McGuire <lmc@winsim.com> - 2011-09-06 14:13 -0500
      Re: does virtualizing all methods slow C++ down ? jacob navia <jacob@spamsink.net> - 2011-09-06 21:57 +0200
        Re: does virtualizing all methods slow C++ down ? Alain Ketterlin <alain@dpt-info.u-strasbg.fr> - 2011-09-06 22:40 +0200
          Re: does virtualizing all methods slow C++ down ? Lynn McGuire <lmc@winsim.com> - 2011-09-06 16:13 -0500
            Re: does virtualizing all methods slow C++ down ? Jorgen Grahn <grahn+nntp@snipabacken.se> - 2011-09-07 08:01 +0000
              Re: does virtualizing all methods slow C++ down ? Lynn McGuire <lmc@winsim.com> - 2011-09-14 12:08 -0500
                Re: does virtualizing all methods slow C++ down ? Lynn McGuire <lmc@winsim.com> - 2011-09-14 14:04 -0500
        Re: does virtualizing all methods slow C++ down ? Lynn McGuire <lmc@winsim.com> - 2011-09-06 16:11 -0500
          Re: does virtualizing all methods slow C++ down ? Paavo Helde <myfirstname@osa.pri.ee> - 2011-09-07 11:44 -0500
            Re: does virtualizing all methods slow C++ down ? Joshua Maurice <joshuamaurice@gmail.com> - 2011-09-07 14:11 -0700
              Re: does virtualizing all methods slow C++ down ? Paavo Helde <myfirstname@osa.pri.ee> - 2011-09-08 01:26 -0500
              Re: does virtualizing all methods slow C++ down ? Nobody <nobody@nowhere.com> - 2011-09-08 07:37 +0100
              Re: does virtualizing all methods slow C++ down ? zindorsky <nephi.allred@gmail.com> - 2011-09-09 10:20 -0700
                Re: does virtualizing all methods slow C++ down ? "Kevin P. Fleming" <news@kpfleming.us> - 2011-09-10 11:48 -0400
                Re: does virtualizing all methods slow C++ down ? Nobody <nobody@nowhere.com> - 2011-09-10 17:58 +0100
  Re: does virtualizing all methods slow C++ down ? Juha Nieminen <nospam@thanks.invalid> - 2011-09-07 06:19 +0000
  Re: does virtualizing all methods slow C++ down ? Goran <goran.pusic@gmail.com> - 2011-09-06 23:52 -0700
    Re: does virtualizing all methods slow C++ down ? Juha Nieminen <nospam@thanks.invalid> - 2011-09-07 07:57 +0000
      Re: does virtualizing all methods slow C++ down ? Jorgen Grahn <grahn+nntp@snipabacken.se> - 2011-09-07 10:39 +0000
      Re: does virtualizing all methods slow C++ down ? Goran <goran.pusic@gmail.com> - 2011-09-07 04:30 -0700
        Re: does virtualizing all methods slow C++ down ? Juha Nieminen <nospam@thanks.invalid> - 2011-09-07 13:04 +0000
          Re: does virtualizing all methods slow C++ down ? Goran <goran.pusic@gmail.com> - 2011-09-07 06:18 -0700
  Re: does virtualizing all methods slow C++ down ? ld <laurent.deniau@gmail.com> - 2011-09-08 05:34 -0700

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