1.\" $OpenBSD: islower.3,v 1.12 2013/07/17 05:42:11 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 17 2013 $ 35.Dt ISLOWER 3 36.Os 37.Sh NAME 38.Nm islower 39.Nd lower-case character test 40.Sh SYNOPSIS 41.In ctype.h 42.Ft int 43.Fn islower "int c" 44.Sh DESCRIPTION 45The 46.Fn islower 47function tests for any lower-case letter 48.\" or any of an 49.\" implementation-defined set of characters 50for which none of 51.Xr iscntrl 3 , 52.Xr isdigit 3 , 53.Xr ispunct 3 , 54or 55.Xr isspace 3 56is true. 57In the C locale, 58.Fn islower 59returns true only for the characters defined as lower-case letters. 60.Sh RETURN VALUES 61The 62.Fn islower 63function returns zero if the character tests false or 64non-zero if the character tests true. 65.Sh SEE ALSO 66.Xr isalnum 3 , 67.Xr isalpha 3 , 68.Xr isascii 3 , 69.Xr isblank 3 , 70.Xr iscntrl 3 , 71.Xr isdigit 3 , 72.Xr isgraph 3 , 73.Xr isprint 3 , 74.Xr ispunct 3 , 75.Xr isspace 3 , 76.Xr isupper 3 , 77.Xr isxdigit 3 , 78.Xr stdio 3 , 79.Xr toascii 3 , 80.Xr tolower 3 , 81.Xr toupper 3 , 82.Xr ascii 7 83.Sh STANDARDS 84The 85.Fn islower 86function conforms to 87.St -ansiC . 88.Sh HISTORY 89The 90.Fn islower 91function first appeared in 92.At v7 . 93.Sh CAVEATS 94The argument to 95.Fn islower 96must be 97.Dv EOF 98or representable as an 99.Li unsigned char ; 100otherwise, the result is undefined. 101