1.\" Copyright (c) 1991 The Regents of the University of California. 2.\" All rights reserved. 3.\" 4.\" This code is derived from software contributed to Berkeley by 5.\" the American National Standards Committee X3, on Information 6.\" Processing Systems. 7.\" 8.\" %sccs.include.redist.man% 9.\" 10.\" @(#)islower.3 5.2 (Berkeley) 06/29/91 11.\" 12.Dd 13.Dt ISLOWER 3 14.Os 15.Sh NAME 16.Nm islower 17.Nd lower-case character test 18.Sh SYNOPSIS 19.Fd #include <ctype.h> 20.Ft int 21.Fn islower "int c" 22.Sh DESCRIPTION 23The 24.Fn islower 25function tests for any lower-case letter 26.\" or any of an 27.\" implementation-defined set of characters 28for which none of 29.Xr iscntrl 3 , 30.Xr isdigit 3 , 31.Xr ispunct 3 , 32or 33.Xr isspace 3 34is true. 35In the 36.Em ``C'' 37locale, 38.Fn islower 39returns true only for the characters defined as lower-case letters. 40.Sh RETURN VALUES 41The 42.Fn islower 43macro returns zero if the character tests false and 44returns non-zero if the character tests true. 45.Sh SEE ALSO 46.Xr isascii 3 , 47.Xr isalnum 3 , 48.Xr isalpha 3 , 49.Xr iscntrl 3 , 50.Xr isdigit 3 , 51.Xr isgraph 3 , 52.Xr isprint 3 , 53.Xr ispunct 3 , 54.Xr isspace 3 , 55.Xr isupper 3 , 56.Xr isxdigit 3 , 57.Xr toascii 3 , 58.Xr tolower 3 , 59.Xr toupper 3 , 60.Xr stdio 3 61.Xr ascii 7 62.Sh STANDARDS 63The 64.Fn islower 65function conforms to 66.St -ansiC . 67