1.\" $OpenBSD: isxdigit.3,v 1.12 2022/09/11 06:38:10 jmc Exp $ 2.\" 3.\" Copyright (c) 1991 The Regents of the University of California. 4.\" Copyright (c) 2017 Ingo Schwarze <schwarze@openbsd.org> 5.\" All rights reserved. 6.\" 7.\" This code is derived from software contributed to Berkeley by 8.\" the American National Standards Committee X3, on Information 9.\" Processing Systems. 10.\" 11.\" Redistribution and use in source and binary forms, with or without 12.\" modification, are permitted provided that the following conditions 13.\" are met: 14.\" 1. Redistributions of source code must retain the above copyright 15.\" notice, this list of conditions and the following disclaimer. 16.\" 2. Redistributions in binary form must reproduce the above copyright 17.\" notice, this list of conditions and the following disclaimer in the 18.\" documentation and/or other materials provided with the distribution. 19.\" 3. Neither the name of the University nor the names of its contributors 20.\" may be used to endorse or promote products derived from this software 21.\" without specific prior written permission. 22.\" 23.\" THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 24.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 25.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 26.\" ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 27.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 28.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 29.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 30.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 31.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 32.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 33.\" SUCH DAMAGE. 34.\" 35.Dd $Mdocdate: September 11 2022 $ 36.Dt ISXDIGIT 3 37.Os 38.Sh NAME 39.Nm isxdigit , 40.Nm isxdigit_l 41.Nd hexadecimal-digit single-byte character test 42.Sh SYNOPSIS 43.In ctype.h 44.Ft int 45.Fn isxdigit "int c" 46.Ft int 47.Fn isxdigit_l "int c" "locale_t locale" 48.Sh DESCRIPTION 49The 50.Fn isxdigit 51and 52.Fn isxdigit_l 53functions test for any hexadecimal-digit character. 54.Pp 55In the C locale, the complete list of hexadecimal digits 56is 0, 1\(en9, A\(enF, and a\(enf. 57.Ox 58always uses the C locale for these functions, 59ignoring the global locale, the thread-specific locale, and the 60.Fa locale 61argument. 62.Sh RETURN VALUES 63These functions return zero if the character tests false or 64non-zero if the character tests true. 65.Sh ENVIRONMENT 66On systems supporting non-ASCII single-byte character encodings, 67these functions may return non-zero for additional characters, 68and the results of 69.Fn isxdigit 70may depend on the 71.Ev LC_CTYPE 72.Xr locale 1 . 73.Sh SEE ALSO 74.Xr isalnum 3 , 75.Xr isalpha 3 , 76.Xr isascii 3 , 77.Xr isblank 3 , 78.Xr iscntrl 3 , 79.Xr isdigit 3 , 80.Xr isgraph 3 , 81.Xr islower 3 , 82.Xr isprint 3 , 83.Xr ispunct 3 , 84.Xr isspace 3 , 85.Xr isupper 3 , 86.Xr iswxdigit 3 , 87.Xr stdio 3 , 88.Xr toascii 3 , 89.Xr tolower 3 , 90.Xr toupper 3 , 91.Xr ascii 7 92.Sh STANDARDS 93The 94.Fn isxdigit 95function conforms to 96.St -ansiC , 97and 98.Fn isxdigit_l 99to 100.St -p1003.1-2008 . 101.Sh HISTORY 102The 103.Fn isxdigit 104function first appeared in 105.At v7 , 106and 107.Fn isdigit_l 108has been available since 109.Ox 6.2 . 110.Sh CAVEATS 111The argument 112.Fa c 113must be 114.Dv EOF 115or representable as an 116.Vt unsigned char ; 117otherwise, the result is undefined. 118