This function has the similar semantics with send(). The only
difference is that it accepts a GnuTLS session, and uses different
Note that if the send buffer is full, send() will block this
function. See the send() documentation for full information. You
can replace the default push function by using
gnutls_transport_set_ptr2() with a call to send() with a
MSG_DONTWAIT flag if blocking is a problem.
If the EINTR is returned by the internal push function (the
default is send()} then GNUTLS_E_INTERRUPTED will be returned. If
GNUTLS_E_INTERRUPTED or GNUTLS_E_AGAIN is returned, you must
call this function again, with the same parameters; alternatively
you could provide a NULL pointer for data, and 0 for
size. cf. gnutls_record_get_direction().
the number of bytes sent, or a negative error code. The
number of bytes sent might be less than sizeofdata. The maximum
number of bytes this function can send in a single call depends on
the negotiated maximum record size.