iswalpha

Standard C library (libc, -lc)

The iswalpha() function is the wide-character equivalent of the isalpha(3) function. It tests whether wc is a wide character belonging to the wide-character class "alpha".

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'.

The iswalpha() function returns nonzero if wc is a wide character belonging to the wide-character class "alpha". Otherwise, it returns zero.

For an explanation of the terms used in this section, see attributes(7).

C11, POSIX.1-2008.

POSIX.1-2001, C99.

The behavior of iswalpha() depends on the LC_CTYPE category of the current locale.