@deftypefun {void} {gnutls_pkcs11_set_token_function} (gnutls_pkcs11_token_callback_t @var{fn}, void * @var{userdata})
@var{fn}: The token callback

@var{userdata}: data to be supplied to callback

This function will set a callback function to be used when a token
needs to be inserted to continue PKCS 11 operations.

@strong{Since:} 2.12.0
@end deftypefun