NAME
tolower —
upper case to lower case
letter conversion
LIBRARY
Standard C Library (libc, -lc)
SYNOPSIS
#include <ctype.h>
int
tolower(
int
c);
DESCRIPTION
The
tolower() function converts an upper-case letter to the
corresponding lower-case letter.
RETURN VALUES
If the argument is an upper-case letter, the
tolower()
function returns the corresponding lower-case letter if there is one;
otherwise the argument is returned unchanged.
SEE ALSO
ctype(3),
isalnum(3),
isalpha(3),
isascii(3),
iscntrl(3),
isdigit(3),
isgraph(3),
islower(3),
isprint(3),
ispunct(3),
isspace(3),
isupper(3),
isxdigit(3),
stdio(3),
toascii(3),
toupper(3),
ascii(7)
STANDARDS
The
tolower() function conforms to
ANSI
X3.159-1989 (“ANSI C89”).
CAVEATS
The argument to
tolower() must be
EOF
or representable as an
unsigned char; otherwise, the
behavior is undefined. See the
CAVEATS
section of
ctype(3) for more
details.