gnutls_session_ext_register(3) — Linux manual page


gnutls_session_ext_register(3)   gnutls   gnutls_session_ext_register(3)

NAME         top

       gnutls_session_ext_register - API function

SYNOPSIS         top

       #include <gnutls/gnutls.h>

       int gnutls_session_ext_register(gnutls_session_t session, const
       char * name, int id, gnutls_ext_parse_type_t parse_point,
       gnutls_ext_recv_func recv_func, gnutls_ext_send_func send_func,
       gnutls_ext_deinit_data_func deinit_func, gnutls_ext_pack_func
       pack_func, gnutls_ext_unpack_func unpack_func, unsigned flags);

ARGUMENTS         top

       gnutls_session_t session
                   the session for which this extension will be set

       const char * name
                   the name of the extension to register

       int id      the numeric id of the extension

       gnutls_ext_parse_type_t parse_point
                   the parse type of the extension (see

       gnutls_ext_recv_func recv_func
                   a function to receive the data

       gnutls_ext_send_func send_func
                   a function to send the data

       gnutls_ext_deinit_data_func deinit_func
                   a function deinitialize any private data

       gnutls_ext_pack_func pack_func
                   a function which serializes the extension's private
                   data (used on session packing for resumption)

       gnutls_ext_unpack_func unpack_func
                   a function which will deserialize the extension's
                   private data

       unsigned flags
                   must be zero or flags from gnutls_ext_flags_t

DESCRIPTION         top

       This function will register a new extension type. The extension
       will be only usable within the registered session. If the
       extension type is already registered then
       GNUTLS_E_ALREADY_REGISTERED will be returned, unless the flag
       GNUTLS_EXT_FLAG_OVERRIDE_INTERNAL is specified. The latter flag
       when specified can be used to override certain extensions
       introduced after 3.6.0. It is expected to be used by applications
       which handle custom extensions that are not currently supported
       in GnuTLS, but direct support for them may be added in the

       Each registered extension can store temporary data into the
       gnutls_session_t structure using gnutls_ext_set_data(), and they
       can be retrieved using gnutls_ext_get_data().

       The validity of the extension registered can be given by the
       appropriate flags of gnutls_ext_flags_t. If no validity is given,
       then the registered extension will be valid for client and TLS1.2
       server hello (or encrypted extensions for TLS1.3).

RETURNS         top

       GNUTLS_E_SUCCESS on success, otherwise a negative error code.

SINCE         top


REPORTING BUGS         top

       Report bugs to <>.
       Home page:

COPYRIGHT         top

       Copyright © 2001-2023 Free Software Foundation, Inc., and others.
       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         top

       The full documentation for gnutls is maintained as a Texinfo
       manual.  If the /usr/share/doc/gnutls/ directory does not contain
       the HTML form visit

COLOPHON         top

       This page is part of the GnuTLS (GnuTLS Transport Layer Security
       Library) project.  Information about the project can be found at
       ⟨⟩.  If you have a bug report for this
       manual page, send it to  This page was obtained
       from the tarball gnutls-3.8.5.tar.xz fetched from
       ⟨⟩ on 2024-06-14.  If you
       discover any rendering problems in this HTML version of the page,
       or you believe there is a better or more up-to-date source for
       the page, or you have corrections or improvements to the
       information in this COLOPHON (which is not part of the original
       manual page), send a mail to

gnutls                            3.8.5   gnutls_session_ext_register(3)