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From: Tim Rentsch <tr.17687@z991.linuxsc.com>
Newsgroups: comp.lang.c
Subject: Re: Baby X is bor nagain
Date: Thu, 20 Jun 2024 22:34:02 -0700
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Malcolm McLean <malcolm.arthur.mclean@gmail.com> writes:

> On 20/06/2024 16:05, Tim Rentsch wrote:
>
[.. on qsort compare function ..]

>> My reading of the C standard is that the comparison function
>> must impose a total ordering on the elements actually present
>> in the array, or is undefined behavior if it does not.  In
>> other words it's okay if the comparison function doesn't
>> define a proper order relation, as long as there are no
>> inconsistencies between values that actually occur in the
>> particular array being sorted.
>
> Yes, a qsort written in the natural way can getstuck if a
> sub0array it considered sorted becmes not sortted on the next
> pass.

Not get stuck.  The array might not be sorted correctly,
but the algorithm doesn't get stuck.