If you're alluding to NUL, I don't really see the issue? Yes, many languages allow strings (UTF-8 or otherwise) to contain null bytes, and C's str*() functions

If you're alluding to NUL, I don't really see the issue? Yes, many languages allow strings (UTF-8 or otherwise) to contain null bytes, and C's str*() functions obviously do not, but null-termination vs not is an orthogonal issue to ASCII vs UTF-8. i.e. Yes it's (depending on context) an issue that C str*() cannot handle strings with embedded null bytes, but that's not a UTF-8-specific issue.