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From: David Brown <david.brown@hesbynett.no>
Newsgroups: comp.arch
Subject: Re: Computer architects leaving Intel...
Date: Sun, 1 Sep 2024 22:12:34 +0200
Organization: A noiseless patient Spider
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References: <2024Aug31.170347@mips.complang.tuwien.ac.at>
 <memo.20240901112118.19028G@jgd.cix.co.uk>
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On 01/09/2024 12:21, John Dallman wrote:
> In article <2024Aug31.170347@mips.complang.tuwien.ac.at>,
> anton@mips.complang.tuwien.ac.at (Anton Ertl) wrote:
> 
>> Undefined behaviour is something that is exercised at run-time.
>> That's why the "undefined behaviour sanitizers" insert run-time
>> checks.  And of course they only detect the behaviour when it is
>> actually exercised.  I.e., they usually will not detect overflowable
>> buffers, because your usual test inputs don't exercise those.
> 
> That's among the many reasons why there is no single way "to make code
> secure." For string buffers, you turn on the compiler run-time checks,
> and use the length-checking versions of string handling functions. Then
> you write tests to check both of those are actually working.
> 
> Then you discover that the C++ string[] operator is not bounds-checked,
> as per the C++ standard, but string.at() is bounds-checked, and curse a
> bit.
> 

But surely you would discover that before using the std::string type?  I 
might do some quick test code using "stuff copied off the internet", but 
for any serious programming I would want to read the specifications of a 
type or function before using it.  That's the only way to be sure you 
are writing correct code.