NAME

islower — lower-case character test

LIBRARY

Standard C Library (libc, -lc)

SYNOPSIS

#include <ctype.h>

int
islower(int c);

DESCRIPTION

The islower() function tests for any lower-case letter for which none of iscntrl(3), isdigit(3), ispunct(3), or isspace(3) is true. In the ``C'' locale, islower() returns true only for the characters defined as lower-case letters.

RETURN VALUES

The islower() function returns zero if the character tests false and returns non-zero if the character tests true.

SEE ALSO

ctype(3), isalnum(3), isalpha(3), isascii(3), isblank(3), iscntrl(3), isdigit(3), isgraph(3), isprint(3), ispunct(3), isspace(3), isupper(3), isxdigit(3), stdio(3), toascii(3), tolower(3), toupper(3), ascii(7)

STANDARDS

The islower() function conforms to ANSI X3.159-1989 (“ANSI C89”).

CAVEATS

The argument to islower() must be EOF or representable as an unsigned char; otherwise, the behavior is undefined. See the CAVEATS section of ctype(3) for more details.