@deftypefun {void} {gnutls_heartbeat_enable} (gnutls_session_t @var{session}, unsigned int @var{type}) @var{session}: is a @code{gnutls_session_t} type. @var{type}: one of the GNUTLS_HB_* flags If this function is called with the @code{GNUTLS_HB_PEER_ALLOWED_TO_SEND} @code{type} , GnuTLS will allow heartbeat messages to be received. Moreover it also request the peer to accept heartbeat messages. This function must be called prior to TLS handshake. If the @code{type} used is @code{GNUTLS_HB_LOCAL_ALLOWED_TO_SEND} , then the peer will be asked to accept heartbeat messages but not send ones. The function @code{gnutls_heartbeat_allowed()} can be used to test Whether locally generated heartbeat messages can be accepted by the peer. @strong{Since:} 3.1.2 @end deftypefun