1.\" Copyright (c) 1989, 1991 The Regents of the University of California. 2.\" All rights reserved. 3.\" 4.\" @(#)tolower.3 5.1 (Berkeley) 05/02/91 5.\" %sccs.include.redist.man% 6.\" 7.\" @(#)tolower.3 5.1 (Berkeley) 05/02/91 8.\" 9.Dd 10.Dt TOLOWER 3 11.Os 12.Sh NAME 13.Nm tolower 14.Nd upper case to lower case letter conversion 15.Sh SYNOPSIS 16.Fd #include <ctype.h> 17.Ft int 18.Fn tolower "int c" 19.Sh DESCRIPTION 20The 21.Fn tolower 22function converts an upper-case letter to the corresponding lower-case 23letter. 24.Sh RETURN VALUES 25If the argument is an upper-case letter, the 26.Fn tolower 27function returns the corresponding lower-case letter if there is 28one; otherwise the argument is returned unchanged. 29.\" In the 30.\" .Em ``C'' 31.\" locale, 32.\" .Fn tolower 33.\" maps only the characters for which 34.\" .Xr isupper 35.\" is true to the corresponding characters for which 36.\" .Xr islower 37.\" is true. 38.Sh SEE ALSO 39.Xr isascii 3 , 40.Xr isalnum 3 , 41.Xr isalpha 3 , 42.Xr iscntrl 3 , 43.Xr isdigit 3 , 44.Xr isgraph 3 , 45.Xr islower 3 , 46.Xr isprint 3 , 47.Xr ispunct 3 , 48.Xr isspace 3 , 49.Xr isupper 3 , 50.Xr isxdigit 3 , 51.Xr toascii 3 , 52.Xr toupper 3 , 53.Xr stdio 3 54.Xr ascii 7 55.Sh STANDARDS 56The 57.Fn tolower 58function conforms to 59.St -ansiC . 60