1.\" $NetBSD: isalpha.3,v 1.11 2003/08/07 16:42:51 agc 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.\" @(#)isalpha.3 5.2 (Berkeley) 6/29/91 35.\" 36.Dd June 29, 1991 37.Dt ISALPHA 3 38.Os 39.Sh NAME 40.Nm isalpha 41.Nd alphabetic character test 42.Sh LIBRARY 43.Lb libc 44.Sh SYNOPSIS 45.In ctype.h 46.Ft int 47.Fn isalpha "int c" 48.Sh DESCRIPTION 49The 50.Fn isalpha 51function tests for any character for which 52.Xr isupper 3 53or 54.Xr islower 3 55is true and 56.\" , or any of an implementation-defined set of characters 57for which none of 58.Xr iscntrl 3 , 59.Xr isdigit 3 , 60.Xr ispunct 3 , 61or 62.Xr isspace 3 63is true. 64In the 65.Em ``C'' 66locale, 67.Fn isalpha 68returns true only for the characters for which 69.Xr isupper 3 70or 71.Xr islower 3 72is true. 73.Sh RETURN VALUES 74The 75.Fn isalpha 76macro returns zero if the character tests false and 77returns non-zero if the character tests true. 78.Sh SEE ALSO 79.Xr isalnum 3 , 80.Xr isascii 3 , 81.Xr isblank 3 , 82.Xr iscntrl 3 , 83.Xr isdigit 3 , 84.Xr isgraph 3 , 85.Xr islower 3 , 86.Xr isprint 3 , 87.Xr ispunct 3 , 88.Xr isspace 3 , 89.Xr isupper 3 , 90.Xr isxdigit 3 , 91.Xr stdio 3 , 92.Xr toascii 3 , 93.Xr tolower 3 , 94.Xr toupper 3 , 95.Xr ascii 7 96.Sh STANDARDS 97The 98.Fn isalpha 99function conforms to 100.St -ansiC . 101.Sh CAVEATS 102The argument to 103.Fn isalpha 104must be 105.Dv EOF 106or representable as an 107.Li unsigned char ; 108otherwise, the result is undefined. 109