In my experience, most applications of C libraries are used in places where security is irrelevant, but even if it mattered, there are of course ways to write C

In my experience, most applications of C libraries are used in places where security is irrelevant, but even if it mattered, there are of course ways to write C without carelessly throwing around pointers. For example, an AIFF to WAV converter likely doesn't need to allocate any memory at all, it just takes a buffer with a length and writes to a buffer with a length. It's very easy to prove correctness of a large number of library decoders/encoders, but of course there are others which may be difficult.