@deftypefun {unsigned} {gnutls_hmac_get_key_size} (gnutls_mac_algorithm_t @var{algorithm})
@var{algorithm}: the mac algorithm to use

This function will return the size of the key to be used with this
algorithm. On the algorithms which may accept arbitrary key sizes,
the returned size is the MAC key size used in the TLS protocol.

@strong{Returns:} The key size or zero on error.

@strong{Since:} 3.6.12
@end deftypefun