@deftypefun {int} {gnutls_pkcs7_sign} (gnutls_pkcs7_t @var{pkcs7}, gnutls_x509_crt_t @var{signer}, gnutls_privkey_t @var{signer_key}, const gnutls_datum_t * @var{data}, gnutls_pkcs7_attrs_t @var{signed_attrs}, gnutls_pkcs7_attrs_t @var{unsigned_attrs}, gnutls_digest_algorithm_t @var{dig}, unsigned @var{flags})
@var{pkcs7}: should contain a @code{gnutls_pkcs7_t}  type

@var{signer}: the certificate to sign the structure

@var{signer_key}: the key to sign the structure

@var{data}: The data to be signed or @code{NULL}  if the data are already embedded

@var{signed_attrs}: Any additional attributes to be included in the signed ones (or @code{NULL} )

@var{unsigned_attrs}: Any additional attributes to be included in the unsigned ones (or @code{NULL} )

@var{dig}: The digest algorithm to use for signing

@var{flags}: Should be zero or one of @code{GNUTLS_PKCS7}  flags

This function will add a signature in the provided PKCS @code{7}  structure
for the provided data. Multiple signatures can be made with different
signers.

The available flags are:
@code{GNUTLS_PKCS7_EMBED_DATA} , @code{GNUTLS_PKCS7_INCLUDE_TIME} , @code{GNUTLS_PKCS7_INCLUDE_CERT} ,
and @code{GNUTLS_PKCS7_WRITE_SPKI} . They are explained in the @code{gnutls_pkcs7_sign_flags} 
definition.

@strong{Returns:} On success, @code{GNUTLS_E_SUCCESS}  (0) is returned, otherwise a
negative error value.

@strong{Since:} 3.4.2
@end deftypefun