bool is_character_file(file_status s) noexcept;
bool is_character_file(const path& p);
bool is_character_file(const path& p, error_code& ec) noexcept;
Returns: is_character_file(status(p))
or is_character_file(status(p, ec)),
respectively.
The signature with argument ec returns false
if an error occurs.
Throws: As specified in [fs.err.report].