TOLOWER(3) BSD Library Functions Manual TOLOWER(3)NAME
tolower, tolower_l — upper case to lower case letter conversion
LIBRARY
Standard C Library (libc, -lc)
SYNOPSIS
#include <ctype.h>
int
tolower(int c);
#include <ctype.h>
#include <xlocale.h>
int
tolower_l(int c, locale_t loc);
DESCRIPTION
The tolower() function converts an upper-case letter to the corresponding
lower-case letter. The argument must be representable as an unsigned
char or the value of EOF.
Although the tolower() function uses the current locale, the tolower_l()
function may be passed a locale directly. See xlocale(3) for more infor‐
mation.
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 argu‐
ment is returned unchanged.
COMPATIBILITY
The 4.4BSD extension of accepting arguments outside of the range of the
unsigned char type in locales with large character sets is considered
obsolete and may not be supported in future releases. The towlower()
function should be used instead.
SEE ALSOctype(3), islower(3), towlower(3), xlocale(3)STANDARDS
The tolower() function conforms to ISO/IEC 9899:1990 (“ISO C90”).
BSD July 17, 2005 BSD
