@deftypefun {int} {gnutls_pubkey_export2} (gnutls_pubkey_t @var{key}, gnutls_x509_crt_fmt_t @var{format}, gnutls_datum_t * @var{out})
@var{key}: Holds the certificate

@var{format}: the format of output params. One of PEM or DER.

@var{out}: will contain a certificate PEM or DER encoded

This function will export the public key to DER or PEM format.
The contents of the exported data is the SubjectPublicKeyInfo
X.509 structure.

The output buffer will be allocated using @code{gnutls_malloc()} .

If the structure is PEM encoded, it will have a header
of "BEGIN CERTIFICATE".

@strong{Returns:} In case of failure a negative error code will be
returned, and 0 on success.

@strong{Since:} 3.1.3
@end deftypefun