TOLOWER(3)             FreeBSD 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);

     int
     tolower_l(int c, locale_t loc);

DESCRIPTION

     The tolower() and tolower_l() functions convert an upper-case letter to
     the corresponding lower-case letter.  The argument must be representable
     as an unsigned char or the value of EOF.

     The tolower_l() function takes an explicit locale argument, whereas the
     tolower() function uses the current global or per-thread locale.

RETURN VALUES

     If the argument is an upper-case letter, the tolower() and tolower_l()
     functions return the corresponding lower-case letter if there is one;
     otherwise, the argument 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() or
     towlower_l() function should be used instead.

SEE ALSO

     ctype(3), ctype_l(3), islower(3), islower_l(3), towlower(3),
     towlower_l(3), xlocale(3)

STANDARDS

     The tolower() function conforms to ISO/IEC 9899:1990 ("ISO C90").

FreeBSD 15.1-STABLE-HBSD       December 19, 2022                    TOLOWER(3)