=head1 DESCRIPTION
SSL_read() tries to read B<num> bytes from the specified B<ssl> into the
-buffer B<buf>. If necessary, SSL_read() will negotiate a TLS/SSL session, if
+buffer B<buf>.
+
+=head1 NOTES
+
+If necessary, SSL_read() will negotiate a TLS/SSL session, if
not already explicitly performed by SSL_connect() or SSL_accept(). If the
peer requests a re-negotiation, it will be performed transparently during
the SSL_read() operation. The behaviour of SSL_read() depends on the
underlying BIO.
If the underlying BIO is B<blocking>, SSL_read() will only return, once the
-read operation has been finished or an error occurred.
+read operation has been finished or an error occurred, except when a
+renegotiation take place, in which case a SSL_ERROR_WANT_READ may occur.
+This behaviour can be controlled with the SSL_MODE_AUTO_RETRY flag of the
+L<SSL_CTX_set_mode(3)|SSL_CTX_set_mode(3)> call.
If the underlying BIO is B<non-blocking>, SSL_read() will also return
when the underlying BIO could not satisfy the needs of SSL_read()
for the required condition. When using a buffering BIO, like a BIO pair, data
must be written into or retrieved out of the BIO before being able to continue.
+=head1 WARNING
+
+When an SSL_read() operation has to be repeated because of
+B<SSL_ERROR_WANT_READ> or B<SSL_ERROR_WANT_WRITE>, it must be repeated
+with the same arguments.
+
=head1 RETURN VALUES
The following return values can occur:
available. Call SSL_get_error() with the return value B<ret> to find out,
whether an error occurred.
-=item -1
+=item E<lt>0
The read operation was not successful, because either an error occurred
or action must be taken by the calling process. Call SSL_get_error() with the
=head1 SEE ALSO
L<SSL_get_error(3)|SSL_get_error(3)>, L<SSL_write(3)|SSL_write(3)>,
+L<SSL_CTX_set_mode(3)|SSL_CTX_set_mode(3)>,
L<ssl(3)|ssl(3)>, L<bio(3)|bio(3)>
=cut