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Giving C a superpower: custom header file (safe_c.h)

(hwisnu.bearblog.dev)
271 points mithcs | 2 comments | 17 Nov 25 10:40 UTC | HN request time: 0.001s | source
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throwaway889900 ◴[17 Nov 25 16:36 UTC] No.45955220[source]▶
Does the StringView/Span implementation here seem lacking? If the underlying data goes away, wouldn't the pointer now point to an invalid freed location, because it doesn't track the underlying data in any way?
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loeg ◴[17 Nov 25 22:30 UTC] No.45959150[source]▶
That's what std::string_view and std::span are, though. They're views / borrows over the underlying data, minus the kind of protections something like Rust has about lifetimes of the underlying data vs the borrow.

The benefit of these types is that they're a pair of pointer+size, instead of just a bare pointer without a known size.

replies(1): >>45959477 #
1. throwaway889900 ◴[17 Nov 25 23:06 UTC] No.45959477[source]▶
True, I guess I was expecting if you were reimplementing these with additional protections, why not add the protection using the custom pointer reimplementations to ensure no use after frees. Seems like a missed opportunity.
replies(1): >>45959834 #
2. loeg ◴[17 Nov 25 23:52 UTC] No.45959834[source]▶
I don’t think there is a way to do this generally without GC, and that leads to significant pitfalls anyway (eg in Java you can accidentally end up holding multi-GB strings in memory because a few references to short substrings exist).