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Groups > comp.lang.c++ > #87903
| From | Juha Nieminen <nospam@thanks.invalid> |
|---|---|
| Newsgroups | comp.lang.c++ |
| Subject | Re: R-value references and std::forward |
| Date | 2022-12-14 12:41 +0000 |
| Organization | Aioe.org NNTP Server |
| Message-ID | <tncgah$1tol$1@gioia.aioe.org> (permalink) |
| References | <6d19a662-76a1-4925-bd07-b259836f062bn@googlegroups.com> <jvtj6mFq5jfU1@mid.individual.net> <a4ffe6c9-868a-4a12-9ab2-49094d7466c8n@googlegroups.com> |
Frederick Virchanza Gotham <cauldwell.thomas@gmail.com> wrote: > If I knew for certain that it was an "int&" then why would I bother > using 'forward' on it? std::forward is useful mainly with templated types. It's not all that useful with concrete types. The main idea with std::forward is that it preserves lvalues as lvalues and rvalues as rvalues when passing parameters to other functions (if you don't use std::forward and tried to pass the function parameter directly then an rvalue would decay to an lvalue, because a named variable always decays to an lvalue, unless explicitly cast to an rvalue). In order to do this you need to provide it with the original type of the value you are passing, as a template parameter. This would usually be the original template type that that parameter has.
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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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