@deftypefun {int} {gnutls_pubkey_get_key_usage} (gnutls_pubkey_t @var{key}, unsigned int * @var{usage})
@var{key}: should contain a @code{gnutls_pubkey_t}  type

@var{usage}: If set will return the number of bits of the parameters (may be NULL)

This function will return the key usage of the public key.

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

@strong{Since:} 2.12.0
@end deftypefun