@deftypefun {void} {gnutls_x509_privkey_set_pin_function} (gnutls_x509_privkey_t @var{privkey}, gnutls_pin_callback_t @var{fn}, void * @var{userdata})
@var{privkey}: The certificate structure

@var{fn}: the callback

@var{userdata}: data associated with the callback

This function will set a callback function to be used when
it is required to access a protected object. This function overrides 
the global function set using @code{gnutls_pkcs11_set_pin_function()} .

Note that this callback is used when decrypting a key.

@strong{Since:} 3.4.0
@end deftypefun