1.\" $NetBSD: tolower.3,v 1.8 2002/02/07 07:00:18 ross Exp $ 2.\" 3.\" Copyright (c) 1989, 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. All advertising materials mentioning features or use of this software 19.\" must display the following acknowledgement: 20.\" This product includes software developed by the University of 21.\" California, Berkeley and its contributors. 22.\" 4. Neither the name of the University nor the names of its contributors 23.\" may be used to endorse or promote products derived from this software 24.\" without specific prior written permission. 25.\" 26.\" THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 27.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 28.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 29.\" ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 30.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 31.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 32.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 33.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 34.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 35.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 36.\" SUCH DAMAGE. 37.\" 38.\" @(#)tolower.3 5.2 (Berkeley) 6/29/91 39.\" 40.Dd June 29, 1991 41.Dt TOLOWER 3 42.Os 43.Sh NAME 44.Nm tolower 45.Nd upper case to lower case letter conversion 46.Sh LIBRARY 47.Lb libc 48.Sh SYNOPSIS 49.Fd #include \*[Lt]ctype.h\*[Gt] 50.Ft int 51.Fn tolower "int c" 52.Sh DESCRIPTION 53The 54.Fn tolower 55function converts an upper-case letter to the corresponding lower-case 56letter. 57.Sh RETURN VALUES 58If the argument is an upper-case letter, the 59.Fn tolower 60function returns the corresponding lower-case letter if there is 61one; otherwise the argument is returned unchanged. 62.\" In the 63.\" .Em ``C'' 64.\" locale, 65.\" .Fn tolower 66.\" maps only the characters for which 67.\" .Xr isupper 68.\" is true to the corresponding characters for which 69.\" .Xr islower 70.\" is true. 71.Sh SEE ALSO 72.Xr isalnum 3 , 73.Xr isalpha 3 , 74.Xr isascii 3 , 75.Xr iscntrl 3 , 76.Xr isdigit 3 , 77.Xr isgraph 3 , 78.Xr islower 3 , 79.Xr isprint 3 , 80.Xr ispunct 3 , 81.Xr isspace 3 , 82.Xr isupper 3 , 83.Xr isxdigit 3 , 84.Xr stdio 3 , 85.Xr toascii 3 , 86.Xr toupper 3 , 87.Xr ascii 7 88.Sh STANDARDS 89The 90.Fn tolower 91function conforms to 92.St -ansiC . 93