SSL_shutdown.pod revision 76866 
1=pod
2
3=head1 NAME
4
5SSL_shutdown - shut down a TLS/SSL connection
6
7=head1 SYNOPSIS
8
9 #include <openssl/ssl.h>
10
11 int SSL_shutdown(SSL *ssl);
12
13=head1 DESCRIPTION
14
15SSL_shutdown() shuts down an active TLS/SSL connection. It sends the 
16"close notify" shutdown alert to the peer.
17
18=head1 NOTES
19
20SSL_shutdown() tries to send the "close notify" shutdown alert to the peer.
21Whether the operation succeeds or not, the SSL_SENT_SHUTDOWN flag is set and
22a currently open session is considered closed and good and will be kept in the
23session cache for further reuse.
24
25The behaviour of SSL_shutdown() depends on the underlying BIO. 
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27If the underlying BIO is B<blocking>, SSL_shutdown() will only return once the
28handshake has been finished or an error occurred.
29
30If the underlying BIO is B<non-blocking>, SSL_shutdown() will also return
31when the underlying BIO could not satisfy the needs of SSL_shutdown()
32to continue the handshake. In this case a call to SSL_get_error() with the
33return value of SSL_shutdown() will yield B<SSL_ERROR_WANT_READ> or
34B<SSL_ERROR_WANT_WRITE>. The calling process then must repeat the call after
35taking appropriate action to satisfy the needs of SSL_shutdown().
36The action depends on the underlying BIO. When using a non-blocking socket,
37nothing is to be done, but select() can be used to check for the required
38condition. When using a buffering BIO, like a BIO pair, data must be written
39into or retrieved out of the BIO before being able to continue.
40
41=head1 RETURN VALUES
42
43The following return values can occur:
44
45=over 4
46
47=item 1
48
49The shutdown was successfully completed.
50
51=item 0
52
53The shutdown was not successful. Call SSL_get_error() with the return
54value B<ret> to find out the reason.
55
56=item -1
57
58The shutdown was not successful because a fatal error occurred either
59at the protocol level or a connection failure occurred. It can also occur of
60action is need to continue the operation for non-blocking BIOs.
61Call SSL_get_error() with the return value B<ret> to find out the reason.
62
63=back
64
65=head1 SEE ALSO
66
67L<SSL_get_error(3)|SSL_get_error(3)>, L<SSL_connect(3)|SSL_connect(3)>,
68L<SSL_accept(3)|SSL_accept(3)>, L<SSL_set_shutdown(3)|SSL_set_shutdown(3)>,
69L<SSL_clear(3)|SSL_clear(3), L<SSL_free(3)|SSL_free(3)>,
70L<ssl(3)|ssl(3)>, L<bio(3)|bio(3)>
71
72=cut
73