1.\" $NetBSD: islower.3,v 1.14 2008/04/17 16:25:36 apb 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.\" @(#)islower.3 5.2 (Berkeley) 6/29/91 35.\" 36.Dd April 17, 2008 37.Dt ISLOWER 3 38.Os 39.Sh NAME 40.Nm islower 41.Nd lower-case character test 42.Sh LIBRARY 43.Lb libc 44.Sh SYNOPSIS 45.In ctype.h 46.Ft int 47.Fn islower "int c" 48.Sh DESCRIPTION 49The 50.Fn islower 51function tests for any lower-case letter 52.\" or any of an 53.\" implementation-defined set of characters 54for which none of 55.Xr iscntrl 3 , 56.Xr isdigit 3 , 57.Xr ispunct 3 , 58or 59.Xr isspace 3 60is true. 61In the 62.Em ``C'' 63locale, 64.Fn islower 65returns true only for the characters defined as lower-case letters. 66.Sh RETURN VALUES 67The 68.Fn islower 69function returns zero if the character tests false and 70returns non-zero if the character tests true. 71.Sh SEE ALSO 72.Xr ctype 3 , 73.Xr isalnum 3 , 74.Xr isalpha 3 , 75.Xr isascii 3 , 76.Xr isblank 3 , 77.Xr iscntrl 3 , 78.Xr isdigit 3 , 79.Xr isgraph 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 islower 93function conforms to 94.St -ansiC . 95.Sh CAVEATS 96The argument to 97.Fn islower 98must be 99.Dv EOF 100or representable as an 101.Vt unsigned char ; 102otherwise, the behavior is undefined. 103See the 104.Sx CAVEATS 105section of 106.Xr ctype 3 107for more details. 108