.\"	$NetBSD: isalnum.3,v 1.15 2008/04/17 16:25:36 apb Exp $
.\"
.\" Copyright (c) 1991 The Regents of the University of California.
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.\" This code is derived from software contributed to Berkeley by
.\" the American National Standards Committee X3, on Information
.\" Processing Systems.
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.\"     @(#)isalnum.3	5.2 (Berkeley) 6/29/91
.\"
.Dd April 17, 2008
.Dt ISALNUM 3
.Os
.Sh NAME
.Nm isalnum
.Nd alphanumeric character test
.Sh LIBRARY
.Lb libc
.Sh SYNOPSIS
.In ctype.h
.Ft int
.Fn isalnum "int c"
.Sh DESCRIPTION
The
.Fn isalnum
function tests for any character for which
.Xr isalpha 3
or
.Xr isdigit 3
is true.
.Sh RETURN VALUES
The
.Fn isalnum
function returns zero if the character tests false and
returns non-zero if the character tests true.
.Sh SEE ALSO
.Xr ctype 3 ,
.Xr isalpha 3 ,
.Xr isascii 3 ,
.Xr isblank 3 ,
.Xr iscntrl 3 ,
.Xr isdigit 3 ,
.Xr isgraph 3 ,
.Xr islower 3 ,
.Xr isprint 3 ,
.Xr ispunct 3 ,
.Xr isspace 3 ,
.Xr isupper 3 ,
.Xr isxdigit 3 ,
.Xr stdio 3 ,
.Xr toascii 3 ,
.Xr tolower 3 ,
.Xr toupper 3 ,
.Xr ascii 7
.Sh STANDARDS
The
.Fn isalnum
function conforms to
.St -ansiC .
.Sh CAVEATS
The argument to
.Fn isalnum
must be
.Dv EOF
or representable as an
.Vt unsigned char ;
otherwise, the behavior is undefined.
See the
.Sx CAVEATS
section of
.Xr ctype 3
for more details.