iswalnum(3)

iswalnum3

Test for alphanumeric wide character

Usage

#include <wctype.h>

int iswalnum(wint_t wc);

Library

Standard C library (libc, -lc)

Overview

The iswalnum() function is the wide-character equivalent of the isalnum(3) function. It tests whether wc is a wide character belonging to the wide-character class "alnum".

The wide-character class "alnum" is a subclass of the wide-character class "graph", and therefore also a subclass of the wide-character class "print".

Being a subclass of the wide-character class "print", the wide-character class "alnum" is disjoint from the wide-character class "cntrl".

Being a subclass of the wide-character class "graph", the wide-character class "alnum" is disjoint from the wide-character class "space" and its subclass "blank".

The wide-character class "alnum" is disjoint from the wide-character class "punct".

The wide-character class "alnum" is the union of the wide-character classes "alpha" and "digit". As such, it also contains the wide-character class "xdigit".

The wide-character class "alnum" always contains at least the letters 'A' to 'Z', 'a' to 'z', and the digits '0' to '9'.

Return value

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

Attributes

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

InterfaceAttributeValue
iswalnum()Thread safetyMT-Safe locale

Notes

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

Releases

14 releases since Debian 2.2 (Potato); the text changed 13 times.

  1. 2.2
  2. 3.0
  3. 3.1
  4. 4.0
  5. 5.0
  6. 6.0
  7. 7
  8. 8
  9. 9
  10. 10
  11. 11
  12. 12
  13. 13
  14. Arch

Standards

C11, POSIX.1-2008.

History

POSIX.1-2001, C99.

From man-pages 6.19-1 in Arch Linux 2026-11-01. Parsed by carta from the page's man source.