Update pre9

doc/man3/SSL_CTX_set_read_ahead.pod

@@ -25,12 +25,14 @@ many input bytes as possible (for non-blocking reads) or not. For example if
 B<x> bytes are currently required by OpenSSL, but B<y> bytes are available from
 the underlying BIO (where B<y> > B<x>), then OpenSSL will read all B<y> bytes
 into its buffer (providing that the buffer is large enough) if reading ahead is
-on, or B<x> bytes otherwise. The parameter B<yes> or B<m> should be 0 to ensure
-reading ahead is off, or non zero otherwise.
+on, or B<x> bytes otherwise.
+Setting the parameter B<yes> to 0 turns reading ahead is off, other values turn
+it on.
 SSL_CTX_set_default_read_ahead() is identical to SSL_CTX_set_read_ahead().
 
 SSL_CTX_get_read_ahead() and SSL_get_read_ahead() indicate whether reading
 ahead has been set or not.
+SSL_CTX_get_default_read_ahead() is identical to SSL_CTX_get_read_ahead().
 
 =head1 NOTES
 
@@ -39,6 +41,18 @@ SSL_CTX_get_read_head() and SSL_get_read_ahead() are undefined for DTLS. Setting
 B<read_ahead> can impact the behaviour of the SSL_pending() function
 (see L<SSL_pending(3)>).
 
+Since SSL_read() can return B<SSL_ERROR_WANT_READ> for non-application data
+records, and SSL_has_pending() can't tell the difference between processed and
+unprocessed data, it's recommended that if read ahead is turned on that
+B<SSL_MODE_AUTO_RETRY> is not turned off using SSL_CTX_clear_mode().
+That will prevent getting B<SSL_ERROR_WANT_READ> when there is still a complete
+record availale that hasn't been processed.
+
+If the application wants to continue to use the underlying transport (e.g. TCP
+connection) after the SSL connection is finished using SSL_shutdown() reading
+ahead should be turned off.
+Otherwise the SSL structure might read data that it shouldn't.
+
 =head1 RETURN VALUES
 
 SSL_get_read_ahead() and SSL_CTX_get_read_ahead() return 0 if reading ahead is off,