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Groups > comp.lang.c++ > #82760

Re: Inline functions and locals

From Bonita Montero <Bonita.Montero@gmail.com>
Newsgroups comp.lang.c++
Subject Re: Inline functions and locals
Date 2022-01-12 17:38 +0100
Organization A noiseless patient Spider
Message-ID <srn06k$gad$1@dont-email.me> (permalink)
References <srmvu4$oie$1@gioia.aioe.org>

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Am 12.01.2022 um 17:34 schrieb Muttley@dastardlyhq.com:
> I'm curious as to why returning a reference to a local inside an inline
> function isn't (apparently) allowed. eg:
> 
> #include <iostream>
> #include <string>
> 
> using namespace std;
> 
> inline string &func()
> {
>          string s = "hello";
>          return s;
> }
> 
> 
> 
> int main()
> {
>          cout << func() << endl;
>          return 0;
> }
> 
> This causes a compilation warning with clang and when run prints out garbage
> as you'd expect if it were a non inline. However surely if the function is
> truly inline it should work. Are locals for inlines temporaries created on the
> heap instead of being stored on the same stack as the calling function locals?

Yes, this is UB because the storage of the function and sometimes
the object you return get destructed. Make it thread_local and then
you can return the object from the function and the function can be
called from any thread. Make it static and lock any operations on
it if you want to have a shared object.

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Thread

Inline functions and locals Muttley@dastardlyhq.com - 2022-01-12 16:34 +0000
  Re: Inline functions and locals Bonita Montero <Bonita.Montero@gmail.com> - 2022-01-12 17:38 +0100
  Re: Inline functions and locals James Kuyper <jameskuyper@alumni.caltech.edu> - 2022-01-12 12:47 -0500
  Re: Inline functions and locals Juha Nieminen <nospam@thanks.invalid> - 2022-01-13 07:00 +0000
    Re: Inline functions and locals "Alf P. Steinbach" <alf.p.steinbach@gmail.com> - 2022-01-13 10:45 +0100
      Re: Inline functions and locals Juha Nieminen <nospam@thanks.invalid> - 2022-01-17 12:55 +0000
        Re: Inline functions and locals David Brown <david.brown@hesbynett.no> - 2022-01-17 15:14 +0100
        Re: Inline functions and locals Andrey Tarasevich <andreytarasevich@hotmail.com> - 2022-01-17 10:24 -0800
          Re: Inline functions and locals David Brown <david.brown@hesbynett.no> - 2022-01-17 19:46 +0100
    Re: Inline functions and locals Bonita Montero <Bonita.Montero@gmail.com> - 2022-01-13 11:08 +0100
      Re: Inline functions and locals Andrey Tarasevich <andreytarasevich@hotmail.com> - 2022-01-13 19:30 -0800
  Re: Inline functions and locals Paavo Helde <eesnimi@osa.pri.ee> - 2022-01-13 12:46 +0200
    Re: Inline functions and locals Muttley@dastardlyhq.com - 2022-01-13 15:38 +0000
  Re: Inline functions and locals Andrey Tarasevich <andreytarasevich@hotmail.com> - 2022-01-13 17:51 -0800
    Re: Inline functions and locals Muttley@dastardlyhq.com - 2022-01-14 11:22 +0000
      Re: Inline functions and locals Öö Tiib <ootiib@hot.ee> - 2022-01-14 04:02 -0800
        Re: Inline functions and locals Manfred <invalid@invalid.add> - 2022-01-14 17:30 +0100
          Re: Inline functions and locals Muttley@dastardlyhq.com - 2022-01-14 16:49 +0000
        Re: Inline functions and locals Muttley@dastardlyhq.com - 2022-01-14 16:40 +0000
          Re: Inline functions and locals Öö Tiib <ootiib@hot.ee> - 2022-01-14 11:28 -0800
          Re: Inline functions and locals "Alf P. Steinbach" <alf.p.steinbach@gmail.com> - 2022-01-14 20:29 +0100
      Re: Inline functions and locals James Kuyper <jameskuyper@alumni.caltech.edu> - 2022-01-14 08:34 -0500
        Re: Inline functions and locals James Kuyper <jameskuyper@alumni.caltech.edu> - 2022-01-14 11:26 -0500
          Re: Inline functions and locals David Brown <david.brown@hesbynett.no> - 2022-01-14 18:47 +0100
      Re: Inline functions and locals Andrey Tarasevich <andreytarasevich@hotmail.com> - 2022-01-14 08:43 -0800
        Re: Inline functions and locals Juha Nieminen <nospam@thanks.invalid> - 2022-01-17 05:38 +0000
          Re: Inline functions and locals David Brown <david.brown@hesbynett.no> - 2022-01-17 08:12 +0100
            Re: Inline functions and locals "Chris M. Thomasson" <chris.m.thomasson.1@gmail.com> - 2022-01-16 23:51 -0800
              Re: Inline functions and locals "Chris M. Thomasson" <chris.m.thomasson.1@gmail.com> - 2022-01-16 23:55 -0800
              Re: Inline functions and locals David Brown <david.brown@hesbynett.no> - 2022-01-17 11:35 +0100
            Re: Inline functions and locals Juha Nieminen <nospam@thanks.invalid> - 2022-01-17 09:50 +0000
              Re: Inline functions and locals James Kuyper <jameskuyper@alumni.caltech.edu> - 2022-01-17 14:39 -0500
                Re: Inline functions and locals Tim Rentsch <tr.17687@z991.linuxsc.com> - 2022-01-17 15:34 -0800
                Re: Inline functions and locals "james...@alumni.caltech.edu" <jameskuyper@alumni.caltech.edu> - 2022-01-17 15:50 -0800
                Re: Inline functions and locals Tim Rentsch <tr.17687@z991.linuxsc.com> - 2022-04-25 03:42 -0700
                Re: Inline functions and locals "james...@alumni.caltech.edu" <jameskuyper@alumni.caltech.edu> - 2022-04-25 08:48 -0700
          Re: Inline functions and locals Andrey Tarasevich <andreytarasevich@hotmail.com> - 2022-01-16 23:53 -0800
            Re: Inline functions and locals Tim Rentsch <tr.17687@z991.linuxsc.com> - 2022-01-17 15:29 -0800
    Re: Inline functions and locals Bonita Montero <Bonita.Montero@gmail.com> - 2022-01-17 12:40 +0100
      Re: Inline functions and locals Andrey Tarasevich <andreytarasevich@hotmail.com> - 2022-01-17 10:13 -0800
        Re: Inline functions and locals James Kuyper <jameskuyper@alumni.caltech.edu> - 2022-01-17 16:15 -0500
          Re: Inline functions and locals Andrey Tarasevich <andreytarasevich@hotmail.com> - 2022-01-17 16:28 -0800
            Re: Inline functions and locals James Kuyper <jameskuyper@alumni.caltech.edu> - 2022-01-17 22:55 -0500
              Re: Inline functions and locals Andrey Tarasevich <andreytarasevich@hotmail.com> - 2022-01-18 11:32 -0800
                Re: Inline functions and locals James Kuyper <jameskuyper@alumni.caltech.edu> - 2022-01-18 19:03 -0500
                Re: Inline functions and locals Andrey Tarasevich <andreytarasevich@hotmail.com> - 2022-01-18 17:22 -0800
        Re: Inline functions and locals Bonita Montero <Bonita.Montero@gmail.com> - 2022-01-18 09:20 +0100

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