.\" Copyright (c) Bruno Haible .\" .\" SPDX-License-Identifier: GPL-2.0-or-later .\" .\" References consulted: .\" GNU glibc-2 source code and manual .\" Dinkumware C library reference http://www.dinkumware.com/ .\" OpenGroup's Single UNIX specification http://www.UNIX-systems.org/online.html .\" ISO/IEC 9899:1999 .\" .TH ISWALNUM 3 2021-03-22 "GNU" "Linux Programmer's Manual" .SH NAME iswalnum \- test for alphanumeric wide character .SH LIBRARY Standard C library .RI ( libc ", " \-lc ) .SH SYNOPSIS .nf .B #include .PP .BI "int iswalnum(wint_t " wc ); .fi .SH DESCRIPTION The .BR iswalnum () function is the wide-character equivalent of the .BR isalnum (3) function. It tests whether .I wc is a wide character belonging to the wide-character class "alnum". .PP 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". .PP Being a subclass of the wide-character class "print", the wide-character class "alnum" is disjoint from the wide-character class "cntrl". .PP 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". .PP The wide-character class "alnum" is disjoint from the wide-character class "punct". .PP 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". .PP The wide-character class "alnum" always contains at least the letters \(aqA\(aq to \(aqZ\(aq, \(aqa\(aq to \(aqz\(aq and the digits \(aq0\(aq to \(aq9\(aq. .SH RETURN VALUE The .BR iswalnum () function returns nonzero if .I wc is a wide character belonging to the wide-character class "alnum". Otherwise, it returns zero. .SH ATTRIBUTES For an explanation of the terms used in this section, see .BR attributes (7). .ad l .nh .TS allbox; lbx lb lb l l l. Interface Attribute Value T{ .BR iswalnum () T} Thread safety MT-Safe locale .TE .hy .ad .sp 1 .SH STANDARDS POSIX.1-2001, POSIX.1-2008, C99. .SH NOTES The behavior of .BR iswalnum () depends on the .B LC_CTYPE category of the current locale. .SH SEE ALSO .BR isalnum (3), .BR iswctype (3)