NAME

     toupper, tolower - convert letter to upper or lower case

SYNOPSIS

     #include <ctype.h>

     int toupper (int c);
     int tolower (int c);

DESCRIPTION

     toupper() converts the letter c to upper case, if possible.

     tolower() converts the letter c to lower case, if possible.

RETURN VALUE

     The value returned is that of the converted letter, or c  if
     the conversion was not possible.

CONFORMING TO

     ANSI - C, BSD 4.3

BUGS

     The details of what constitutes an  uppercase  or  lowercase
     letter  depend  on  the  current  locale.   For example, the
     default "" "C" locale does not know  about  umlauts,  so  no
     conversion is done for them.

     In some non - English locales, there are  lowercase  letters
     with no corresponding uppercase equivalent; the German sharp
     s is one example.

SEE ALSO

     isalpha(3), setlocale(3), locale(7)