NAME
islower —
lower-case character test
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 or non-zero if the character tests true.
SEE ALSO
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”).
HISTORY
The islower() function first appeared in
Version 7 AT&T UNIX.
CAVEATS
The argument to islower() must be
EOF or representable as an unsigned
char; otherwise, the result is undefined.