idna_to_ascii_4i(3)

NAME
idna_to_ascii_4i - API function

SYNOPSIS
#include <idna.h>

int idna_to_ascii_4i(const uint32_t * in, size_t inlen, char * out, int flags);

ARGUMENTS

const uint32_t * in
    input array with unicode code points.

size_t inlen
    length of input array with unicode code points.

char * out
    output zero terminated string that must have room for at least 63 characters plus the terminating zero.

int flags
    an Idna_flags value, e.g., IDNA_ALLOW_UNASSIGNED or IDNA_USE_STD3_ASCII_RULES.

DESCRIPTION
The ToASCII operation takes a sequence of Unicode code points that make up one domain label and transforms it into a sequence of code points in the ASCII range (0..7F). If ToASCII succeeds, the original sequence and the resulting sequence are equivalent labels. It is important to note that the ToASCII operation can fail. ToASCII fails if any step of it fails. If any step of the ToASCII operation fails on any label in a domain name, that domain name MUST NOT be used as an internationalized domain name. The method for deadling with this failure is application-specific. The inputs to ToASCII are a sequence of code points, the AllowUnassigned flag, and the UseSTD3ASCIIRules flag. The output of ToASCII is either a sequence of ASCII code points or a failure condition. ToASCII never alters a sequence of code points that are all in the ASCII range to begin with (although it could fail). Applying the ToASCII operation multiple times has exactly the same effect as applying it just once. Return value: Returns 0 on success, or an Idna_rc error code.

REPORTING BUGS
Report bugs to <help-libidn@gnu.org>.
General guidelines for reporting bugs: https://www.gnu.org/gethelp/
GNU Libidn home page: https://www.gnu.org/software/libidn/

COPYRIGHT
Copyright © 2002-2026 Simon Josefsson.
Copying and distribution of this file, with or without modification, are permitted in any medium without royalty provided the copyright notice and this notice are preserved.

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. As an alternative you may obtain the manual from:

    https://www.gnu.org/software/libidn/manual/