NAME
tolower, _tolower
— upper case to lower case
letter conversion
SYNOPSIS
#include
<ctype.h>
int
tolower(int
c);
int
_tolower(int
c);
DESCRIPTION
The
tolower()
function converts an upper-case letter to the corresponding lower-case
letter. The
_tolower()
function is identical to tolower() except that
c must be an upper-case letter.
RETURN VALUES
If the argument to the tolower() function
is an upper-case letter, the corresponding lower-case letter is returned if
there is one; otherwise the argument is returned unchanged. If the argument
to the _tolower() function is an upper-case letter,
the corresponding lower-case letter is returned; otherwise the output is
undefined.
SEE ALSO
isalnum(3), isalpha(3), isascii(3), isblank(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() and
_tolower() functions conform to
ANSI X3.159-1989
(“ANSI C89”).
CAVEATS
The argument to tolower must be
EOF or representable as an unsigned
char; otherwise, the result is undefined.