text-char-description

text-char-description is a built-in function in `C source code'.

(text-char-description CHARACTER)

Return a pretty description of file-character CHARACTER.
Control characters turn into "^char", etc. This differs from
`single-key-description' which turns them into "C-char".
Also, this function recognizes the 2**7 bit as the Meta character,
whereas `single-key-description' uses the 2**27 bit for Meta.
See Info node `(elisp)Describing Characters' for examples.