The ISO/IEC 9899 standard defines the term "wide character" and the wchar_t and wint_t data types.
A wide character is a representation of a single character that fits into an object of type wchar_t.
The wchar_t is an integer type capable of representing all characters for all supported locales.
The wint_t is an integer type capable of storing any valid value of wchar_t or WEOF.
A wide-character string (also wide string or process code string) is a sequence of wide characters terminated by a null wide character code.
In Oracle Solaris, the internal form of wchar_t is specific to a locale. In the Oracle Solaris Unicode locales, wchar_t has the UTF-32 Unicode encoding form, and other locales have different representations.