.\" Copyright (c) 1989, 1991, 1993
.\"	The Regents of the University of California.  All rights reserved.
.\"
.\" This code is derived from software contributed to Berkeley by
.\" the American National Standards Committee X3, on Information
.\" Processing Systems.
.\"
.\" %sccs.include.redist.man%
.\"
.\"	@(#)tolower.3	8.1 (Berkeley) 06/04/93
.\"
.Dd 
.Dt TOLOWER 3
.Os
.Sh NAME
.Nm tolower
.Nd upper case to lower case letter conversion
.Sh SYNOPSIS
.Fd #include <ctype.h>
.Ft int
.Fn tolower "int c"
.Sh DESCRIPTION
The
.Fn tolower
function converts an upper-case letter to the corresponding lower-case
letter.
.Sh RETURN VALUES
If the argument is an upper-case letter, the
.Fn tolower
function returns the corresponding lower-case letter if there is
one; otherwise the argument is returned unchanged.
.\" In the 
.\" .Em ``C''
.\" locale,
.\" .Fn tolower
.\" maps only the characters for which
.\" .Xr isupper
.\" is true to the corresponding characters for which
.\" .Xr islower
.\" is true.
.Sh SEE ALSO
.Xr isascii 3 ,
.Xr isalnum 3 ,
.Xr isalpha 3 ,
.Xr iscntrl 3 ,
.Xr isdigit 3 ,
.Xr isgraph 3 ,
.Xr islower 3 ,
.Xr isprint 3 ,
.Xr ispunct 3 ,
.Xr isspace 3 ,
.Xr isupper 3 ,
.Xr isxdigit 3 ,
.Xr toascii 3 ,
.Xr toupper 3 ,
.Xr stdio 3
.Xr ascii 7
.Sh STANDARDS
The
.Fn tolower
function conforms to
.St -ansiC .