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You shouldn't be writing C if you're not a careful coder.


Yeah, right.

https://msrc-blog.microsoft.com/2019/07/16/a-proactive-appro...

https://research.google/pubs/pub46800/

https://support.apple.com/guide/security/memory-safe-iboot-i...

Maybe you could give an helping hand to Microsoft, Apple and Google, they are in need of carefull C coders.


I'm not sure if you intentionally missed my point. Everything in C requires careful usage. VLAs aren't special: they're just yet another feature which must be used carefully, if used at all.

Personally, I don't use them, but I don't find "they're unsafe" to be a convincing reason for why they shouldn't be included in the already-unsafe language. Saying they're unnecessary might be a better reason.


The goal should be to reduce the amount of sharp edges, not increase them even further.


VLAs are unsafe in the worst kind of way as it is not possible to query when it is safe to use them. alloca() at least in theory can return null stack overflow, but there is no such provision with VLA.


They're not unsafe (in the memory sense) as long as they check for overflow and reliably crash if there is one.


If a lot of platforms don't implement this check reliably, then it's unsafe in practice at this time, even if not in theory.


Who out there has a version of stack checking that doesn't actually check the stack…? If it doesn't check by default, as C doesn't, then it's not "as long as".


And if you're a careful coder writing C, you should give the VLA the stink eye unless it's proving its worth.


Hint, that means nobody should be writing C.


Where is the lie?


Too bad we have all that legacy C code that won't just reappear by itself on a safer language.

That means there are a lot of not careful enough developers (AKA, human ones) that will write a lot of C just because they need some change here or there.




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