@deftypefun {void} {gnutls_transport_set_push_function} (gnutls_session_t @var{session}, gnutls_push_func @var{push_func})
@var{session}: is a @code{gnutls_session_t}  type.

@var{push_func}: a callback function similar to @code{write()} 

This is the function where you set a push function for gnutls to
use in order to send data.  If you are going to use berkeley style
sockets, you do not need to use this function since the default
send(2) will probably be ok.  Otherwise you should specify this
function for gnutls to be able to send data.
The callback should return a positive number indicating the
bytes sent, and -1 on error.

 @code{push_func} is of the form,
ssize_t (*gnutls_push_func)(gnutls_transport_ptr_t, const void*, size_t);
@end deftypefun