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From: Mateusz Viste <mateusz@x.invalid>
Newsgroups: comp.lang.c
Subject: Re: Memory protection between compilation units?
Date: Fri, 13 Jun 2025 08:59:27 +0200
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On Thu, 12 Jun 2025 06:05 Tim Rentsch wrote:
> The code in question shows several classic error patterns.  In no
> particular order:
> 
>   * buffer overflow
>   * off-by-one error

I'd consider that one item, since one leads to another.

>   * bitwise operator with signed operand

My mistake. Real code is acting on something else than an int, I wasn't
paying enough attention when writing the illustrative example.

>   * using & to effect what is really a modulo operation

You think of it as modulo, I think of it as "bits trimming".
Essentially same operation, but different viewpoints I guess.

> I acknowledge that this response isn't exactly an answer to the
> original question.  It does illustrate though a kind of thinking
> that can be useful when trying to track down hard-to-find bugs.

Thank you for your insightful remarks. I completely agree - the best
way to debug a program is to avoid the need for debugging in the first
place. :-) But working with a large, 15-year-old codebase that has
seen contributions from dozens of programmers makes things a bit
non-ideal sometimes.

Mateusz