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From: Kaz Kylheku <433-929-6894@kylheku.com>
Newsgroups: comp.lang.c
Subject: Re: A Famous Security Bug
Date: Sat, 23 Mar 2024 16:07:47 -0000 (UTC)
Organization: A noiseless patient Spider
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Message-ID: <20240323090700.848@kylheku.com>
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On 2024-03-23, David Brown <david.brown@hesbynett.no> wrote:
> On 22/03/2024 20:43, Kaz Kylheku wrote:
>> On 2024-03-22, Keith Thompson <Keith.S.Thompson+u@gmail.com> wrote:
>>> Is the "call" instruction *observable behavior* as defined in 5.1.2.3?
>> 
>
>
>>> Running a program under a test harness is effectively running a
>>> different program.  Of course it can yield information about the
>>> original program, but in effect you're linking the program with a
>>> different set of libraries.
>> 
>> It's a different program, but the retained translation unit must be the
>> same, except that the external references it makes are resolved to
>> different entities.
>
> That is true - /if/ you make the restriction that the translation unit 
> is complied completely to linkable machine code or assembly, and that it 
> is not changed in any way when it is combined into the new program. 
> Such a setup is common in practice, but it is in no way required by the 
> C standards and does not apply for more advanced compilation and build 
> scenarios.

Well, it's only not required if you hand-wave away the sentences in
section 5.

You can't just do that!