idn2_lookup_ul(3)

NAME
idn2_lookup_ul - API function

SYNOPSIS
#include <idn2.h>

int idn2_lookup_ul(const char * src, char ** lookupname, int flags);

ARGUMENTS

const char * src
    input zero-terminated locale encoded string.

char ** lookupname
    newly allocated output variable with name to lookup in DNS.

int flags
    optional idn2_flags to modify behaviour.

DESCRIPTION
Perform IDNA2008 lookup string conversion on domain name src , as described in section 5 of RFC 5891. Note that the input is assumed to be encoded in the locale's default coding system, and will be transcoded to UTF-8 and NFC normalized by this function.

Pass IDN2_ALABEL_ROUNDTRIP in flags to convert any input A-labels to U-labels and perform additional testing. This is default since version 2.2. To switch this behavior off, pass IDN2_NO_ALABEL_ROUNDTRIP

Pass IDN2_TRANSITIONAL to enable Unicode TR46 transitional processing, and IDN2_NONTRANSITIONAL to enable Unicode TR46 non-transitional processing.

Multiple flags may be specified by binary or:ing them together, for example IDN2_ALABEL_ROUNDTRIP | IDN2_NONTRANSITIONAL.

The IDN2_NFC_INPUT in flags is always enabled in this function.

After version 0.11: lookupname may be NULL to test lookup of src without allocating memory.

RETURNS
On successful conversion IDN2_OK is returned, if conversion from locale to UTF-8 fails then IDN2_ICONV_FAIL is returned, if the output domain or any label would have been too long IDN2_TOO_BIG_DOMAIN or IDN2_TOO_BIG_LABEL is returned, or another error code is returned.

SINCE
0.1

REPORTING BUGS
Report bugs to <help-libidn@gnu.org>.
General guidelines for reporting bugs: https://www.gnu.org/gethelp/
Libidn2 home page: https://www.gnu.org/software/libidn2/

COPYRIGHT
Copyright © 2002-2025 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 libidn2 is maintained as a Texinfo manual. If the info and libidn2 programs are properly installed at your site, the command

    info libidn2

should give you access to the complete manual. As an alternative you may obtain the manual from:

    https://www.gnu.org/software/libidn/libidn2/manual/