@deftypefun {int} {gnutls_x509_crq_set_private_key_usage_period} (gnutls_x509_crq_t @var{crq}, time_t @var{activation}, time_t @var{expiration})
@var{crq}: a certificate of type @code{gnutls_x509_crq_t} 

@var{activation}: The activation time

@var{expiration}: The expiration time

This function will set the private key usage period extension (2.5.29.16).

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