1.\" $OpenBSD: isalpha.3,v 1.12 2013/07/18 10:14:48 schwarze Exp $ 2.\" 3.\" Copyright (c) 1991 The Regents of the University of California. 4.\" All rights reserved. 5.\" 6.\" This code is derived from software contributed to Berkeley by 7.\" the American National Standards Committee X3, on Information 8.\" Processing Systems. 9.\" 10.\" Redistribution and use in source and binary forms, with or without 11.\" modification, are permitted provided that the following conditions 12.\" are met: 13.\" 1. Redistributions of source code must retain the above copyright 14.\" notice, this list of conditions and the following disclaimer. 15.\" 2. Redistributions in binary form must reproduce the above copyright 16.\" notice, this list of conditions and the following disclaimer in the 17.\" documentation and/or other materials provided with the distribution. 18.\" 3. Neither the name of the University nor the names of its contributors 19.\" may be used to endorse or promote products derived from this software 20.\" without specific prior written permission. 21.\" 22.\" THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 23.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 24.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 25.\" ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 26.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 27.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 28.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 29.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 30.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 31.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 32.\" SUCH DAMAGE. 33.\" 34.Dd $Mdocdate: July 18 2013 $ 35.Dt ISALPHA 3 36.Os 37.Sh NAME 38.Nm isalpha 39.Nd alphabetic character test 40.Sh SYNOPSIS 41.In ctype.h 42.Ft int 43.Fn isalpha "int c" 44.Sh DESCRIPTION 45The 46.Fn isalpha 47function tests for any character for which 48.Xr isupper 3 49or 50.Xr islower 3 51is true and 52.\" , or any of an implementation-defined set of characters 53for which none of 54.Xr iscntrl 3 , 55.Xr isdigit 3 , 56.Xr ispunct 3 , 57or 58.Xr isspace 3 59is true. 60In the C locale, 61.Fn isalpha 62returns true only for the characters for which 63.Xr isupper 3 64or 65.Xr islower 3 66is true. 67.Sh RETURN VALUES 68The 69.Fn isalpha 70function returns zero if the character tests false or 71non-zero if the character tests true. 72.Sh SEE ALSO 73.Xr isalnum 3 , 74.Xr isascii 3 , 75.Xr isblank 3 , 76.Xr iscntrl 3 , 77.Xr isdigit 3 , 78.Xr isgraph 3 , 79.Xr islower 3 , 80.Xr isprint 3 , 81.Xr ispunct 3 , 82.Xr isspace 3 , 83.Xr isupper 3 , 84.Xr isxdigit 3 , 85.Xr stdio 3 , 86.Xr toascii 3 , 87.Xr tolower 3 , 88.Xr toupper 3 , 89.Xr ascii 7 90.Sh STANDARDS 91The 92.Fn isalpha 93function conforms to 94.St -ansiC . 95.Sh HISTORY 96The 97.Fn isalpha 98function first appeared in 99.At v7 . 100.Sh CAVEATS 101The argument to 102.Fn isalpha 103must be 104.Dv EOF 105or representable as an 106.Li unsigned char ; 107otherwise, the result is undefined. 108