1.\" Copyright (c) 1991, 1993 2.\" The Regents of the University of California. All rights reserved. 3.\" 4.\" This code is derived from software contributed to Berkeley by 5.\" the American National Standards Committee X3, on Information 6.\" Processing Systems. 7.\" 8.\" Redistribution and use in source and binary forms, with or without 9.\" modification, are permitted provided that the following conditions 10.\" are met: 11.\" 1. Redistributions of source code must retain the above copyright 12.\" notice, this list of conditions and the following disclaimer. 13.\" 2. Redistributions in binary form must reproduce the above copyright 14.\" notice, this list of conditions and the following disclaimer in the 15.\" documentation and/or other materials provided with the distribution. 16.\" 3. Neither the name of the University nor the names of its contributors 17.\" may be used to endorse or promote products derived from this software 18.\" without specific prior written permission. 19.\" 20.\" THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 21.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 22.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 23.\" ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 24.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 25.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 26.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 27.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 28.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 29.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 30.\" SUCH DAMAGE. 31.\" 32.Dd December 19, 2022 33.Dt ISXDIGIT 3 34.Os 35.Sh NAME 36.Nm isxdigit , 37.Nm ishexnumber , 38.Nm isxdigit_l , 39.Nm ishexnumber_l 40.Nd hexadecimal-digit character test 41.Sh LIBRARY 42.Lb libc 43.Sh SYNOPSIS 44.In ctype.h 45.Ft int 46.Fn isxdigit "int c" 47.Ft int 48.Fn ishexnumber "int c" 49.Ft int 50.Fn isxdigit_l "int c" "locale_t loc" 51.Ft int 52.Fn ishexnumber_l "int c" "locale_t loc" 53.Sh DESCRIPTION 54The 55.Fn isxdigit 56and 57.Fn isxdigit_l 58functions test for any hexadecimal-digit character. 59Regardless of locale, this includes the following characters only: 60.Bl -column \&``0''______ \&``0''______ \&``0''______ \&``0''______ \&``0''______ 61.It "\&``0''" Ta "``1''" Ta "``2''" Ta "``3''" Ta "``4''" 62.It "\&``5''" Ta "``6''" Ta "``7''" Ta "``8''" Ta "``9''" 63.It "\&``A''" Ta "``B''" Ta "``C''" Ta "``D''" Ta "``E''" 64.It "\&``F''" Ta "``a''" Ta "``b''" Ta "``c''" Ta "``d''" 65.It "\&``e''" Ta "``f''" Ta \& Ta \& Ta \& 66.El 67.Pp 68The 69.Fn ishexnumber 70and 71.Fn ishexnumber_l 72functions behave similarly to 73.Fn isxdigit 74and 75.Fn isxdigit_l , 76but may recognize additional characters, 77depending on the current locale setting. 78.Pp 79The value of the argument must be representable as an 80.Vt "unsigned char" 81or the value of 82.Dv EOF . 83.Pp 84The _l-suffixed versions take an explicit locale argument, whereas the 85non-suffixed versions use the current global or per-thread locale. 86.Sh RETURN VALUES 87The 88.Fn isxdigit 89and 90.Fn isxdigit_l 91functions return zero if the character tests false and 92return non-zero if the character tests true. 93.Sh COMPATIBILITY 94The 95.Bx 4.4 96extension of accepting arguments outside of the range of the 97.Vt "unsigned char" 98type in locales with large character sets is considered obsolete 99and may not be supported in future releases. 100The 101.Fn iswxdigit 102or 103.Fn iswxdigit_l 104function should be used instead. 105.Sh SEE ALSO 106.Xr ctype 3 , 107.Xr ctype_l 3 , 108.Xr iswxdigit 3 , 109.Xr iswxdigit_l 3 , 110.Xr xlocale 3 , 111.Xr ascii 7 112.Sh STANDARDS 113The 114.Fn isxdigit 115function conforms to 116.St -isoC . 117.Sh HISTORY 118The 119.Fn ishexnumber 120function appeared in 121.Bx 4.4 . 122