http://kor.i2p/books/The%20C%20Programming%20Language%20by%20K&R/appa.html
Extended characters are also new. The character
sets commonly used in the Americas and western Europe can be encoded to fit
in the char type; the main intent in adding wchar_t was to
accommodate Asian languages. A.2.5.3 Floating Constants A floating constant consists of an integer part, a decimal part, a fraction
part, an e or E , an optionally signed integer exponent and an
optional type suffix, one of f , F , l , or L .