@deftypefun {void} {gnutls_transport_set_pull_function} (gnutls_session_t @var{session}, gnutls_pull_func @var{pull_func})
@var{session}: is a @code{gnutls_session_t}  type.

@var{pull_func}: a callback function similar to @code{read()} 

This is the function where you set a function for gnutls to receive
data.  Normally, if you use berkeley style sockets, do not need to
use this function since the default recv(2) will probably be ok.
The callback should return 0 on connection termination, a positive
number indicating the number of bytes received, and -1 on error.

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