SSL_connect.pod revision 279264 
1=pod
2
3=head1 NAME
4
5SSL_connect - initiate the TLS/SSL handshake with an TLS/SSL server
6
7=head1 SYNOPSIS
8
9 #include <openssl/ssl.h>
10
11 int SSL_connect(SSL *ssl);
12
13=head1 DESCRIPTION
14
15SSL_connect() initiates the TLS/SSL handshake with a server. The communication
16channel must already have been set and assigned to the B<ssl> by setting an
17underlying B<BIO>.
18
19=head1 NOTES
20
21The behaviour of SSL_connect() depends on the underlying BIO. 
22
23If the underlying BIO is B<blocking>, SSL_connect() will only return once the
24handshake has been finished or an error occurred.
25
26If the underlying BIO is B<non-blocking>, SSL_connect() will also return
27when the underlying BIO could not satisfy the needs of SSL_connect()
28to continue the handshake, indicating the problem by the return value -1.
29In this case a call to SSL_get_error() with the
30return value of SSL_connect() will yield B<SSL_ERROR_WANT_READ> or
31B<SSL_ERROR_WANT_WRITE>. The calling process then must repeat the call after
32taking appropriate action to satisfy the needs of SSL_connect().
33The action depends on the underlying BIO. When using a non-blocking socket,
34nothing is to be done, but select() can be used to check for the required
35condition. When using a buffering BIO, like a BIO pair, data must be written
36into or retrieved out of the BIO before being able to continue.
37
38=head1 RETURN VALUES
39
40The following return values can occur:
41
42=over 4
43
44=item Z<>0
45
46The TLS/SSL handshake was not successful but was shut down controlled and
47by the specifications of the TLS/SSL protocol. Call SSL_get_error() with the
48return value B<ret> to find out the reason.
49
50=item Z<>1
51
52The TLS/SSL handshake was successfully completed, a TLS/SSL connection has been
53established.
54
55=item E<lt>0
56
57The TLS/SSL handshake was not successful, because a fatal error occurred either
58at the protocol level or a connection failure occurred. The shutdown was
59not clean. It can also occur of action is need to continue the operation
60for non-blocking BIOs. Call SSL_get_error() with the return value B<ret>
61to find out the reason.
62
63=back
64
65=head1 SEE ALSO
66
67L<SSL_get_error(3)|SSL_get_error(3)>, L<SSL_accept(3)|SSL_accept(3)>,
68L<SSL_shutdown(3)|SSL_shutdown(3)>, L<ssl(3)|ssl(3)>, L<bio(3)|bio(3)>,
69L<SSL_set_connect_state(3)|SSL_set_connect_state(3)>,
70L<SSL_do_handshake(3)|SSL_do_handshake(3)>,
71L<SSL_CTX_new(3)|SSL_CTX_new(3)>
72
73=cut
74