@deftypefun {int} {gnutls_certificate_set_key} (gnutls_certificate_credentials_t @var{res}, const char ** @var{names}, int @var{names_size}, gnutls_pcert_st * @var{pcert_list}, int @var{pcert_list_size}, gnutls_privkey_t @var{key})
@var{res}: is a @code{gnutls_certificate_credentials_t}  type.

@var{names}: is an array of DNS names belonging to the public-key (NULL if none)

@var{names_size}: holds the size of the names list

@var{pcert_list}: contains a certificate list (chain) or raw public-key

@var{pcert_list_size}: holds the size of the certificate list

@var{key}: is a @code{gnutls_privkey_t}  key corresponding to the first public-key in pcert_list

This function sets a public/private key pair in the
gnutls_certificate_credentials_t type. The given public key may be encapsulated
in a certificate or can be given as a raw key. This function may be
called more than once, in case multiple key pairs exist for
the server. For clients that want to send more than their own end-
entity certificate (e.g., also an intermediate CA cert), the full
certificate chain must be provided in  @code{pcert_list} .

Note that the  @code{key} will become part of the credentials structure and must
not be deallocated. It will be automatically deallocated when the  @code{res} structure
is deinitialized.

If this function fails, the  @code{res} structure is at an undefined state and it must
not be reused to load other keys or certificates.

Note that, this function by default returns zero on success and a negative value on error.
Since 3.5.6, when the flag @code{GNUTLS_CERTIFICATE_API_V2}  is set using @code{gnutls_certificate_set_flags()} 
it returns an index (greater or equal to zero). That index can be used for other functions to refer to the added key-pair.

Since GnuTLS 3.6.6 this function also handles raw public keys.

@strong{Returns:} On success this functions returns zero, and otherwise a negative value on error (see above for modifying that behavior).

@strong{Since:} 3.0
@end deftypefun