#include <wctype.h> int iswalpha(wint_t wc);
The wide-character class "alpha" is a subclass of the wide-character class "alnum", and therefore also a subclass of the wide-character class "graph" and of the wide-character class "print".
Being a subclass of the wide-character class "print", the wide-character class "alpha" is disjoint from the wide-character class "cntrl".
Being a subclass of the wide-character class "graph", the wide-character class "alpha" is disjoint from the wide-character class "space" and its subclass "blank".
Being a subclass of the wide-character class "alnum", the wide-character class "alpha" is disjoint from the wide-character class "punct".
The wide-character class "alpha" is disjoint from the wide-character class "digit".
The wide-character class "alpha" contains the wide-character classes "upper" and "lower".
The wide-character class "alpha" always contains at least the letters 'A' to 'Z' and 'a' to 'z'.
| Interface | Attribute | Value |
| iswalpha() | Thread safety | MT-Safe locale |