Wide character subroutines

Wide character subroutines process characters in process-code form. Wide character subroutines usually start with a wc prefix. However, there are exceptions to this rule. For example, the wide character classification functions use an isw prefix. To determine if a subroutine is a wide character subroutine, check if the subroutine prototype defines characters as wchar_t data type or wchar_t data pointer, or else check whether the subroutine returns a wchar_t data type. There are some exceptions to this rule. For example, the wide character classification subroutines accept wint_t data type values.