wchar.h header file

The wchar.h header file declares information that is necessary for programming with multibyte and wide character subroutines. The wchar.h header file declares the wchar_t, wctype_t, and wint_t data types, as well as several functions for testing wide characters. Because the number of characters implemented as wide characters exceeds that of basic characters, it is not possible to classify all wide characters into the existing classes used for basic characters. Therefore, it is necessary to provide a way of defining additional classes specific to some locale. The action of these subroutines is affected by the current locale.

The wchar.h header file also declares subroutines for manipulating wide character strings (that is, wchar_t data type arrays). Array length is always determined in terms of the number of wchar_t elements in an array. A null wide character code ends an array. A pointer to a wchar_t data type array or void array always points to the initial element of the array.