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Re: A counterintuitive breaking change related to new comparisons

From Andrey Tarasevich <andreytarasevich@hotmail.com>
Newsgroups comp.lang.c++
Subject Re: A counterintuitive breaking change related to new comparisons
Date 2022-01-03 16:33 -0800
Organization A noiseless patient Spider
Message-ID <sr04ld$39j$1@dont-email.me> (permalink)
References <sqvcts$h94$1@dont-email.me> <20220103210610.ec3859f4d0b23edfc9d217c3@cvine--nospam--.freeserve.co.uk> <sqvsdu$trp$1@dont-email.me> <20220104002324.1c51f5d1cced60e8e79a75ec@cvine--nospam--.freeserve.co.uk>

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On 1/3/2022 4:23 PM, Chris Vine wrote:
> Ah yes, I misread your code.  You are not comparing pointers, you are
> comparing indeterminate values.  I would need to look it up but my
> recollection is that reading (and so comparing) an uninitialized value
> also comprises undefined behaviour, unless it is of unsigned char or
> std::byte type.  Here you seem to be comparing an uninitialized int and
> char (via S:: operator <) type.

No. That is incorrect. All values involved in these comparisons are 
perfectly initialized.

Both `std::pair` objects are initialized with their default 
constructors, which in turn perform value-initialization of their 
members. In my example all `std::pair`s fields are guaranteed to be 
initialized to zero. Nothing indeterminate here.

-- 
Best regards,
Andrey Tarasevich .

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Thread

A counterintuitive breaking change related to new comparisons Andrey Tarasevich <andreytarasevich@hotmail.com> - 2022-01-03 09:48 -0800
  Re: A counterintuitive breaking change related to new comparisons Chris Vine <chris@cvine--nospam--.freeserve.co.uk> - 2022-01-03 21:06 +0000
    Re: A counterintuitive breaking change related to new comparisons Andrey Tarasevich <andreytarasevich@hotmail.com> - 2022-01-03 14:13 -0800
      Re: A counterintuitive breaking change related to new comparisons Chris Vine <chris@cvine--nospam--.freeserve.co.uk> - 2022-01-04 00:23 +0000
        Re: A counterintuitive breaking change related to new comparisons Andrey Tarasevich <andreytarasevich@hotmail.com> - 2022-01-03 16:33 -0800
          Re: A counterintuitive breaking change related to new comparisons Juha Nieminen <nospam@thanks.invalid> - 2022-01-04 08:27 +0000
            Re: A counterintuitive breaking change related to new comparisons "Alf P. Steinbach" <alf.p.steinbach@gmail.com> - 2022-01-04 17:24 +0100
            Re: A counterintuitive breaking change related to new comparisons Andrey Tarasevich <andreytarasevich@hotmail.com> - 2022-01-04 10:26 -0800
        Re: A counterintuitive breaking change related to new comparisons Chris Vine <chris@cvine--nospam--.freeserve.co.uk> - 2022-01-04 00:39 +0000
  Re: A counterintuitive breaking change related to new comparisons Andrey Tarasevich <andreytarasevich@hotmail.com> - 2022-01-03 14:24 -0800
    Re: A counterintuitive breaking change related to new comparisons "Alf P. Steinbach" <alf.p.steinbach@gmail.com> - 2022-01-03 23:55 +0100
    Re: A counterintuitive breaking change related to new comparisons Manfred <noname@add.invalid> - 2022-01-04 00:56 +0100
      Re: A counterintuitive breaking change related to new comparisons Manfred <noname@add.invalid> - 2022-01-04 00:59 +0100
      Re: A counterintuitive breaking change related to new comparisons Andrey Tarasevich <andreytarasevich@hotmail.com> - 2022-01-03 16:59 -0800
        Re: A counterintuitive breaking change related to new comparisons Chris Vine <chris@cvine--nospam--.freeserve.co.uk> - 2022-01-04 01:27 +0000
        Re: A counterintuitive breaking change related to new comparisons Öö Tiib <ootiib@hot.ee> - 2022-01-04 14:49 -0800
          Re: A counterintuitive breaking change related to new comparisons Öö Tiib <ootiib@hot.ee> - 2022-01-04 15:16 -0800
          Re: A counterintuitive breaking change related to new comparisons Andrey Tarasevich <andreytarasevich@hotmail.com> - 2022-01-05 09:06 -0800
  Re: A counterintuitive breaking change related to new comparisons "Chris M. Thomasson" <chris.m.thomasson.1@gmail.com> - 2022-01-03 18:51 -0800
  Re: A counterintuitive breaking change related to new comparisons wij <wyniijj@gmail.com> - 2022-01-04 03:53 -0800
    Re: A counterintuitive breaking change related to new comparisons wij <wyniijj@gmail.com> - 2022-01-04 21:59 -0800

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