为什么C11或C ++ 11中没有ASCII或UTF-8字符文字？

Why is there no UTF-8 character literal in C11 or C++11 even though there are UTF-8 string literals? I understand that, generally-speaking, a character literal represents a single ASCII character which is identical to a single-octet UTF-8 code point, but neither C nor C++ says the encoding has to be ASCII.Why is there no UTF-8 character literal in C11