[ssokolow]

Yes. In practical terms, because optimizers like GCC and LLVM track uninitialized values and it's undefined behaviour to read from them, so you essentially have a split between what memory is allocated from the perspective of write operations (capacity) and what memory is allocated from the perspective of read operations (length).

On an academic level, memory safety is split into "spatial" and "temporal" cases and one that Wikipedia calls "spatiotemporal", with reading off the end of "capacity" being a spatial memory safety bug and reading within "capacity" before initializing being a temporal memory safety bug.

The other temporal memory safety types as Wikipedia enumerates them are:

* Use after free

* Double free

* Mismatched free (stuff like not using the free() from the same DLL that called malloc(), mixing up malloc/free with new/delete, etc.)