How and where, in principle, do you suppose it should (be able to) do so, given the functionality? It's just localizing timestamps, and the result might bubble through multiple layers of software before being presented to anyone. It's not as if C APIs get designed up front to return structures with a boolean "btw you called this in a nonstandard way that might fuck up in the future" flag (or, say, a pointer to a deprecation-warning structure; and then that interface has to be rock-solid stable to be of use) for every call. And if they did, nobody would ever write code that checks it.

> How and where, in principle, do you suppose it should (be able to) do so, given the functionality?

System logs?

> It's not as if C APIs get designed up front to return structures with a boolean "btw you called this in a nonstandard way that might fuck up in the future" flag (or, say, a pointer to a deprecation-warning structure; and then that interface has to be rock-solid stable to be of use) for every call. And if they did, nobody would ever write code that checks it.

Yeah, fair point, no-one should be using a C API at this point.