SYNOPSIS
       #include <punycode.h>

       int  punycode_encode(size_t input_length, const punycode_uint [] input,
       const unsigned char [] case_flags, size_t * output_length, char [] out-
       put);

ARGUMENTS
       size_t input_length
                   The number of code points in the input array and the number
                   of flags in the case_flags array.

       const punycode_uint [] input
                   An array of code points.  They are presumed to  be  Unicode
                   code  points, but that is not strictly REQUIRED.  The array
                   contains code points, not code  units.   UTF-16  uses  code
                   units   D800   through   DFFF   to  refer  to  code  points
                   10000..10FFFF.  The code points D800..DFFF do not occur  in
                   any  valid  Unicode string.  The code points that can occur
                   in Unicode strings  (0..D7FF  and  E000..10FFFF)  are  also
                   called Unicode scalar values.

       const unsigned char [] case_flags
                   A  NULL  pointer  or an array of boolean values parallel to
                   the input array.  Nonzero (true, flagged) suggests that the
                   corresponding  Unicode  character  be  forced  to uppercase
                   after  being  decoded  (if  possible),  and  zero   (false,
                   unflagged) suggests that it be forced to lowercase (if pos-
                   sible).  ASCII code points (0..7F) are  encoded  literally,
                   except that ASCII letters are forced to uppercase or lower-
                   case  according  to  the  corresponding  case  flags.    If
                   case_flags is a NULL pointer then ASCII letters are left as
                   they are, and other code points are treated as unflagged.

       size_t * output_length
                   The caller passes in  the  maximum  number  of  ASCII  code
                   points  that  it can receive.  On successful return it will
                   contain the number of ASCII code points actually output.

       char [] output
                   An array of ASCII code points.   It  is  *not*  null-termi-
                   nated;  it will contain zeros if and only if the input con-
                   tains zeros.  (Of course the caller can leave  room  for  a
                   terminator and add one if needed.)

DESCRIPTION
       Converts a sequence of code points (presumed to be Unicode code points)
       to Punycode.

RETURN VALUE
       The return value can be any of the Punycode_status values defined above
       except  PUNYCODE_BAD_INPUT.   If not PUNYCODE_SUCCESS, then output_size
       and output might contain garbage.

SEE ALSO
       The  full  documentation  for libidn is maintained as a Texinfo manual.
       If the info and libidn programs are properly installed  at  your  site,
       the command

              info libidn

       should give you access to the complete manual.