@dalias @ireneista @misty @bob It's more that an API *can* (in plenty of cases) present e.g. something UTF-8 in a POSIX-ish API, etc, but a) perhaps my use case doesn't want that, and b) if it doesn't, the API also may fail to provide it.
I mean, you just have to read https://en.m.wikipedia.org/wiki/Han_unification to understand where Unicode may be a particularly bad choice.