NAME         top

       gnutls_x509_crt_get_subject_alt_name - API function

SYNOPSIS         top

       #include <gnutls/x509.h>

       int gnutls_x509_crt_get_subject_alt_name(gnutls_x509_crt_t cert,
       unsigned int seq, void * san, size_t * san_size, unsigned int *

ARGUMENTS         top

       gnutls_x509_crt_t cert
                   should contain a gnutls_x509_crt_t type

       unsigned int seq
                   specifies the sequence number of the alt name (0 for the
                   first one, 1 for the second etc.)

       void * san  is the place where the alternative name will be copied to

       size_t * san_size
                   holds the size of san.

       unsigned int * critical
                   will be non-zero if the extension is marked as critical
                   (may be null)

DESCRIPTION         top

       This function retrieves the Alternative Name (, contained
       in the given certificate in the X509v3 Certificate Extensions.

       When the SAN type is otherName, it will extract the data in the
       otherName's value field, and GNUTLS_SAN_OTHERNAME is returned.  You
       may use gnutls_x509_crt_get_subject_alt_othername_oid() to get the
       corresponding OID and the "virtual" SAN types (e.g.,

       If an otherName OID is known, the data will be decoded.  Otherwise
       the returned data will be DER encoded, and you will have to decode it
       yourself.  Currently, only the RFC 3920 id-on-xmppAddr SAN is

RETURNS         top

       the alternative subject name type on success, one of the enumerated
       gnutls_x509_subject_alt_name_t.  It will return
       GNUTLS_E_SHORT_MEMORY_BUFFER if  san_size is not large enough to hold
       the value.  In that case  san_size will be updated with the required
       size.  If the certificate does not have an Alternative name with the
       specified sequence number then GNUTLS_E_REQUESTED_DATA_NOT_AVAILABLE
       is returned.

REPORTING BUGS         top

       Report bugs to <>.
       Home page:

COPYRIGHT         top

       Copyright © 2001-2018 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-3.6.2.tar.xz fetched from
       ⟨⟩ on 2018-04-30.  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                              3.g6n.u2tls_x509_crt_get_subject_alt_name(3)