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aw1621107last Sunday at 1:23 PM2 repliesview on HN

I believe the claim is that there's nothing in the C standard that requires implementations to be unsafe. If they wanted to, they could bounds check pointers, check allocations are still alive when pointers are dereferenced, etc. and still be conformant to the standard.


Replies

pornellast Sunday at 8:57 PM

Nothing in the C standard requires bytes to have 8 bits either.

There's a massive gap between what C allows, and what real C codebases can tolerate.

In practice, you don't have room to store lengths along pointers without disturbing sizeof and pointer<>integer casts. Fil-C and ASAN need to smuggle that information out of band.

ueckerlast Sunday at 7:02 PM

Even more, certain rules are specifically designed to make such checks possible while being conformant to the standard.