Re: An argument against (the liberal use of) references

From	Juha Nieminen <nospam@thanks.invalid>
Newsgroups	comp.lang.c++
Subject	Re: An argument against (the liberal use of) references
Date	2022-11-23 06:52 +0000
Organization	Aioe.org NNTP Server
Message-ID	<tlkfv5$rss$1@gioia.aioe.org> (permalink)
References	<tli64v$1k4l$1@gioia.aioe.org> <tlibnk$3298$1@dont-email.me>

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Paavo Helde <eesnimi@osa.pri.ee> wrote:
> If the code passing a reference is not thread-safe, then just changing 
> it to pass by value will not magically make it thread-safe. Without 
> proper synchronization, the object may be changed by another thread at 
> any moment, for example in the middle of the copy operation, and thus 
> the copy might become internally inconsistent.

I think you have a point there. I was thinking that since the function is
getting a local copy of the object then mutual exclusion problems go away
because that local copy is completely independent of the original.

I didn't think that *copying* the object for the function in itself isn't
automatically thread-safe. Yet still, for a few seconds, I had the strong
instinct that there has to be something "more thread-safe" about making
a copy of the value for the function than have the function take a
reference to it... but the more I try to figure out how, I fail. Copying
merely moves the mutual exclusion problem to a slightly different place,
but it doesn't solve it. The calling code *still* needs to solve the
mutual exclusion problem regardless of which way the function takes the
parameter.

Thread

An argument *against* (the liberal use of) references Juha Nieminen <nospam@thanks.invalid> - 2022-11-22 09:52 +0000
  Re: An argument *against* (the liberal use of) references "Fred. Zwarts" <F.Zwarts@KVI.nl> - 2022-11-22 11:23 +0100
  Re: An argument *against* (the liberal use of) references Paavo Helde <eesnimi@osa.pri.ee> - 2022-11-22 13:27 +0200
    Re: An argument *against* (the liberal use of) references Juha Nieminen <nospam@thanks.invalid> - 2022-11-23 06:52 +0000
      Re: An argument *against* (the liberal use of) references "Alf P. Steinbach" <alf.p.steinbach@gmail.com> - 2022-11-23 13:51 +0100
        Re: An argument *against* (the liberal use of) references Juha Nieminen <nospam@thanks.invalid> - 2022-11-23 13:46 +0000
          Re: An argument *against* (the liberal use of) references Paavo Helde <eesnimi@osa.pri.ee> - 2022-11-30 13:59 +0200
            Re: An argument *against* (the liberal use of) references Juha Nieminen <nospam@thanks.invalid> - 2022-12-01 06:45 +0000
              Re: An argument *against* (the liberal use of) references Paavo Helde <eesnimi@osa.pri.ee> - 2022-12-01 09:19 +0200
                Re: An argument *against* (the liberal use of) references Stuart Redmann <DerTopper@web.de> - 2022-12-01 14:06 +0100
                Re: An argument *against* (the liberal use of) references Paavo Helde <eesnimi@osa.pri.ee> - 2022-12-01 16:45 +0200
                Re: An argument *against* (the liberal use of) references scott@slp53.sl.home (Scott Lurndal) - 2022-12-01 16:02 +0000
                Re: An argument *against* (the liberal use of) references Paavo Helde <eesnimi@osa.pri.ee> - 2022-12-01 20:21 +0200
                Re: An argument *against* (the liberal use of) references scott@slp53.sl.home (Scott Lurndal) - 2022-12-01 19:09 +0000
                Re: An argument *against* (the liberal use of) references Michael S <already5chosen@yahoo.com> - 2022-12-02 05:53 -0800
                Re: An argument *against* (the liberal use of) references scott@slp53.sl.home (Scott Lurndal) - 2022-12-02 14:36 +0000
                Re: An argument *against* (the liberal use of) references "Chris M. Thomasson" <chris.m.thomasson.1@gmail.com> - 2022-12-02 12:29 -0800
                Re: An argument *against* (the liberal use of) references scott@slp53.sl.home (Scott Lurndal) - 2022-12-02 20:55 +0000
                Re: An argument *against* (the liberal use of) references "Chris M. Thomasson" <chris.m.thomasson.1@gmail.com> - 2022-12-02 12:58 -0800
                Re: An argument *against* (the liberal use of) references scott@slp53.sl.home (Scott Lurndal) - 2022-12-02 21:18 +0000
                Re: An argument *against* (the liberal use of) references "Chris M. Thomasson" <chris.m.thomasson.1@gmail.com> - 2022-12-02 14:16 -0800
                Re: An argument *against* (the liberal use of) references Branimir Maksimovic <branimir.maksimovic@icloud.com> - 2022-12-02 21:09 +0000
                Re: An argument *against* (the liberal use of) references "Chris M. Thomasson" <chris.m.thomasson.1@gmail.com> - 2022-12-02 13:22 -0800
                Re: An argument *against* (the liberal use of) references Branimir Maksimovic <branimir.maksimovic@icloud.com> - 2022-12-02 21:36 +0000
                Re: An argument *against* (the liberal use of) references "Chris M. Thomasson" <chris.m.thomasson.1@gmail.com> - 2022-12-02 14:13 -0800
                Re: An argument *against* (the liberal use of) references Paavo Helde <eesnimi@osa.pri.ee> - 2022-12-02 18:33 +0200
                Re: An argument *against* (the liberal use of) references Michael S <already5chosen@yahoo.com> - 2022-12-01 11:59 -0800
                Re: An argument *against* (the liberal use of) references Paavo Helde <eesnimi@osa.pri.ee> - 2022-12-01 23:53 +0200
                Re: An argument *against* (the liberal use of) references Michael S <already5chosen@yahoo.com> - 2022-12-02 04:11 -0800
                Re: An argument *against* (the liberal use of) references "Chris M. Thomasson" <chris.m.thomasson.1@gmail.com> - 2022-12-01 12:21 -0800
                Re: An argument *against* (the liberal use of) references Juha Nieminen <nospam@thanks.invalid> - 2022-12-06 11:36 +0000
                Re: An argument *against* (the liberal use of) references "Chris M. Thomasson" <chris.m.thomasson.1@gmail.com> - 2022-12-06 12:26 -0800
                Re: An argument *against* (the liberal use of) references scott@slp53.sl.home (Scott Lurndal) - 2022-12-06 20:39 +0000
                Re: An argument *against* (the liberal use of) references Paavo Helde <eesnimi@osa.pri.ee> - 2022-12-06 23:53 +0200
                Re: An argument *against* (the liberal use of) references "Chris M. Thomasson" <chris.m.thomasson.1@gmail.com> - 2022-12-06 13:59 -0800
                Re: An argument *against* (the liberal use of) references scott@slp53.sl.home (Scott Lurndal) - 2022-12-06 22:04 +0000
                Re: An argument *against* (the liberal use of) references Öö Tiib <ootiib@hot.ee> - 2022-12-06 21:38 -0800
                Re: An argument *against* (the liberal use of) references scott@slp53.sl.home (Scott Lurndal) - 2022-12-07 15:22 +0000
                Re: An argument *against* (the liberal use of) references Paavo Helde <eesnimi@osa.pri.ee> - 2022-12-07 18:37 +0200
                Re: An argument *against* (the liberal use of) references "Chris M. Thomasson" <chris.m.thomasson.1@gmail.com> - 2022-12-06 14:01 -0800
                Re: An argument *against* (the liberal use of) references Juha Nieminen <nospam@thanks.invalid> - 2022-12-07 09:05 +0000
                Re: An argument *against* (the liberal use of) references "Chris M. Thomasson" <chris.m.thomasson.1@gmail.com> - 2022-12-07 12:48 -0800
                Re: An argument *against* (the liberal use of) references "Chris M. Thomasson" <chris.m.thomasson.1@gmail.com> - 2022-12-07 12:50 -0800
                Re: An argument *against* (the liberal use of) references Juha Nieminen <nospam@thanks.invalid> - 2022-12-08 07:52 +0000
                Re: An argument *against* (the liberal use of) references Tim Rentsch <tr.17687@z991.linuxsc.com> - 2022-12-08 05:50 -0800
                Re: An argument *against* (the liberal use of) references Michael S <already5chosen@yahoo.com> - 2022-12-08 13:30 -0800
                Re: An argument *against* (the liberal use of) references Tim Rentsch <tr.17687@z991.linuxsc.com> - 2022-12-09 12:50 -0800
                Re: An argument *against* (the liberal use of) references David Brown <david.brown@hesbynett.no> - 2022-12-11 12:18 +0100
                Re: An argument *against* (the liberal use of) references Paavo Helde <eesnimi@osa.pri.ee> - 2022-12-08 13:38 +0200
                Re: An argument *against* (the liberal use of) references "Chris M. Thomasson" <chris.m.thomasson.1@gmail.com> - 2022-12-08 16:45 -0800
                Re: An argument *against* (the liberal use of) references Malcolm McLean <malcolm.arthur.mclean@gmail.com> - 2022-12-09 04:35 -0800
  Re: An argument *against* (the liberal use of) references Bonita Montero <Bonita.Montero@gmail.com> - 2022-11-22 15:36 +0100
  Re: An argument *against* (the liberal use of) references Chris Vine <chris@cvine--nospam--.freeserve.co.uk> - 2022-11-22 15:21 +0000
  Re: An argument *against* (the liberal use of) references Richard Damon <Richard@Damon-Family.org> - 2022-11-22 10:48 -0500
    Re: An argument *against* (the liberal use of) references "Chris M. Thomasson" <chris.m.thomasson.1@gmail.com> - 2022-11-22 13:18 -0800
  Re: An argument *against* (the liberal use of) references El Jo <giorgio.zoppi@gmail.com> - 2022-11-22 13:41 -0800
    Re: An argument *against* (the liberal use of) references "Chris M. Thomasson" <chris.m.thomasson.1@gmail.com> - 2022-11-22 13:51 -0800
  Re: An argument *against* (the liberal use of) references Bonita Montero <Bonita.Montero@gmail.com> - 2022-11-23 20:08 +0100

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