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Groups > comp.lang.c++ > #87889

Re: R-value references and std::forward

From Bo Persson <bo@bo-persson.se>
Newsgroups comp.lang.c++
Subject Re: R-value references and std::forward
Date 2022-12-14 10:26 +0100
Message-ID <jvtj6mFq5jfU1@mid.individual.net> (permalink)
References <6d19a662-76a1-4925-bd07-b259836f062bn@googlegroups.com>

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On 2022-12-14 at 09:44, Frederick Virchanza Gotham wrote:
> The following code up on GodBolt:
> 
>      https://godbolt.org/z/bfs3qn5Gx
> 
> prints out:
> 
>      Dog takes l-value ref
>      Monkey takes r-value ref
>      Hello
> 
> I expected it to say "Monkey takes l-value ref".
> 
> Is the behaviour undefined because of my use of 'forward' on Line #22? Should 'forward' only be used with a so-called 'template parameter forwarding reference'?
> 

You are using it wrong, anyway. When the value is an int&, you should 
"forward" is using forward<int&>(arg).

That's what happens with a forwarding reference.


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Thread

R-value references and std::forward Frederick Virchanza Gotham <cauldwell.thomas@gmail.com> - 2022-12-14 00:44 -0800
  Re: R-value references and std::forward Bo Persson <bo@bo-persson.se> - 2022-12-14 10:26 +0100
    Re: R-value references and std::forward Frederick Virchanza Gotham <cauldwell.thomas@gmail.com> - 2022-12-14 01:48 -0800
      Re: R-value references and std::forward Bo Persson <bo@bo-persson.se> - 2022-12-14 12:42 +0100
        Re: R-value references and std::forward Frederick Virchanza Gotham <cauldwell.thomas@gmail.com> - 2022-12-14 06:46 -0800
          Re: R-value references and std::forward Öö Tiib <ootiib@hot.ee> - 2022-12-15 05:48 -0800
      Re: R-value references and std::forward Juha Nieminen <nospam@thanks.invalid> - 2022-12-14 12:41 +0000
        Re: R-value references and std::forward Bonita Montero <Bonita.Montero@gmail.com> - 2022-12-15 19:03 +0100
  Re: R-value references and std::forward Bonita Montero <Bonita.Montero@gmail.com> - 2022-12-15 16:39 +0100
  Re: R-value references and std::forward Andrey Tarasevich <andreytarasevich@hotmail.com> - 2022-12-17 10:55 -0800

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