NAME         top

       gnutls_certificate_set_retrieve_function2 - API function

SYNOPSIS         top

       #include <gnutls/abstract.h>

       cred, gnutls_certificate_retrieve_function2 * func);

ARGUMENTS         top

       gnutls_certificate_credentials_t cred
                   is a gnutls_certificate_credentials_t type.

       gnutls_certificate_retrieve_function2 * func
                   is the callback function

DESCRIPTION         top

       This function sets a callback to be called in order to retrieve the
       certificate to be used in the handshake. The callback will take
       control only if a certificate is requested by the peer.

       The callback's function prototype is: int
       (*callback)(gnutls_session_t, const gnutls_datum_t* req_ca_dn, int
       nreqs, const gnutls_pk_algorithm_t* pk_algos, int pk_algos_length,
       gnutls_pcert_st** pcert, unsigned int *pcert_length, gnutls_privkey_t
       * pkey);

        req_ca_dn is only used in X.509 certificates.  Contains a list with
       the CA names that the server considers trusted.  This is a hint and
       typically the client should send a certificate that is signed by one
       of these CAs. These names, when available, are DER encoded. To get a
       more meaningful value use the function gnutls_x509_rdn_get().

        pk_algos contains a list with server's acceptable signature
       algorithms.  The certificate returned should support the server's
       given algorithms.

        pcert should contain a single certificate and public key or a list
       of them.

        pcert_length is the size of the previous list.

        pkey is the private key.

       If the callback function is provided then gnutls will call it, in the
       handshake, after the certificate request message has been received.
       All the provided by the callback values will not be released or
       modified by gnutls.

       In server side pk_algos and req_ca_dn are NULL.

       The callback function should set the certificate list to be sent, and
       return 0 on success. If no certificate was selected then the number
       of certificates should be set to zero. The value (-1) indicates error
       and the handshake will be terminated. If both certificates are set in
       the credentials and a callback is available, the callback takes

SINCE         top


REPORTING BUGS         top

       Report bugs to <>.
       Home page:

COPYRIGHT         top

       Copyright © 2001-2017 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-3.5.9.tar.xz fetched from 
       ⟨⟩ on 2017-03-13.  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

gnutls                          gnut3l.s5_.c9ertificate_set_retrieve_function2(3)