gnutls_certificate_client_set_retrieve_function (3) - Linux Manuals

gnutls_certificate_client_set_retrieve_function: API function


gnutls_certificate_client_set_retrieve_function - API function


#include <gnutls/compat.h>

void gnutls_certificate_client_set_retrieve_function(gnutls_certificate_credentials_t cred, gnutls_certificate_client_retrieve_function * func);


gnutls_certificate_credentials_t cred
is a gnutls_certificate_credentials_t structure.
gnutls_certificate_client_retrieve_function * func
is the callback function


This function sets a callback to be called in order to retrieve the certificate to be used in the handshake. You are advised to use gnutls_certificate_set_retrieve_function2() because it is much more efficient in the processing it requires from gnutls.

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_retr_st* st);

 req_ca_cert is only used in X.509 certificates. Contains a list with the CA names that the server considers trusted. Normally we should send a certificate that is signed by one of these CAs. These names 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.

 st should contain the certificates and private keys.

If the callback function is provided then gnutls will call it, in the handshake, if a certificate is requested by the server (and after the certificate request message has been received).

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.


Report bugs to <bugs [at]>.
Home page:


Copyright © 2001-2014 Free Software Foundation, Inc..
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.


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