@deftypefun {int} {gnutls_session_key_update} (gnutls_session_t @var{session}, unsigned @var{flags})

@var{session}: is a @code{gnutls_session_t}  type.

@var{flags}: zero of @code{GNUTLS_KU_PEER} 

This function will update/refresh the session keys when the

TLS protocol is 1.3 or better. The peer is notified of the

update by sending a message, so this function should be

treated similarly to @code{gnutls_record_send()}  --i.e., it may

return @code{GNUTLS_E_AGAIN}  or @code{GNUTLS_E_INTERRUPTED} .

When this flag @code{GNUTLS_KU_PEER}  is specified, this function

in addition to updating the local keys, will ask the peer to

refresh its keys too.

If the negotiated version is not TLS 1.3 or better this

function will return @code{GNUTLS_E_INVALID_REQUEST} .

@strong{Returns:} @code{GNUTLS_E_SUCCESS}  on success, otherwise a negative error code.

@strong{Since:} 3.6.3

@end deftypefun