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.\" 4. 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.\" @(#)isalpha.3 8.1 (Berkeley) 6/4/93 33.\" $FreeBSD$ 34.\" 35.Dd July 17, 2005 36.Dt ISALPHA 3 37.Os 38.Sh NAME 39.Nm isalpha 40.Nd alphabetic character test 41.Sh LIBRARY 42.Lb libc 43.Sh SYNOPSIS 44.In ctype.h 45.Ft int 46.Fn isalpha "int c" 47.Ft int 48.Fn isalpha_l "int c" "locale_t loc" 49.Sh DESCRIPTION 50The 51.Fn isalpha 52function tests for any character for which 53.Xr isupper 3 54or 55.Xr islower 3 56is true. 57The value of the argument must be representable as an 58.Vt "unsigned char" 59or the value of 60.Dv EOF . 61.Pp 62In the ASCII character set, this includes the following characters 63(with their numeric values shown in octal): 64.Bl -column \&000_``0''__ \&000_``0''__ \&000_``0''__ \&000_``0''__ \&000_``0''__ 65.It "\&101\ ``A''" Ta "102\ ``B''" Ta "103\ ``C''" Ta "104\ ``D''" Ta "105\ ``E''" 66.It "\&106\ ``F''" Ta "107\ ``G''" Ta "110\ ``H''" Ta "111\ ``I''" Ta "112\ ``J''" 67.It "\&113\ ``K''" Ta "114\ ``L''" Ta "115\ ``M''" Ta "116\ ``N''" Ta "117\ ``O''" 68.It "\&120\ ``P''" Ta "121\ ``Q''" Ta "122\ ``R''" Ta "123\ ``S''" Ta "124\ ``T''" 69.It "\&125\ ``U''" Ta "126\ ``V''" Ta "127\ ``W''" Ta "130\ ``X''" Ta "131\ ``Y''" 70.It "\&132\ ``Z''" Ta "141\ ``a''" Ta "142\ ``b''" Ta "143\ ``c''" Ta "144\ ``d''" 71.It "\&145\ ``e''" Ta "146\ ``f''" Ta "147\ ``g''" Ta "150\ ``h''" Ta "151\ ``i''" 72.It "\&152\ ``j''" Ta "153\ ``k''" Ta "154\ ``l''" Ta "155\ ``m''" Ta "156\ ``n''" 73.It "\&157\ ``o''" Ta "160\ ``p''" Ta "161\ ``q''" Ta "162\ ``r''" Ta "163\ ``s''" 74.It "\&164\ ``t''" Ta "165\ ``u''" Ta "166\ ``v''" Ta "167\ ``w''" Ta "170\ ``x''" 75.It "\&171\ ``y''" Ta "172\ ``z''" Ta \& Ta \& Ta \& 76.El 77.Pp 78The 79.Fn isalpha_l 80function takes an explicit locale argument, whereas the 81.Fn isalpha 82function uses the current global or per-thread locale. 83.Sh RETURN VALUES 84The 85.Fn isalpha 86function returns zero if the character tests false and 87returns non-zero if the character tests true. 88.Sh COMPATIBILITY 89The 90.Bx 4.4 91extension of accepting arguments outside of the range of the 92.Vt "unsigned char" 93type in locales with large character sets is considered obsolete 94and may not be supported in future releases. 95The 96.Fn iswalpha 97function should be used instead. 98.Sh SEE ALSO 99.Xr ctype 3 , 100.Xr islower 3 , 101.Xr isupper 3 , 102.Xr iswalpha 3 , 103.Xr xlocale 3 , 104.Xr ascii 7 105.Sh STANDARDS 106The 107.Fn isalpha 108function conforms to 109.St -isoC . 110The 111.Fn isalpha_l 112function conforms to 113.St -p1003.1-2008 . 114