5 SSL_connect - initiate the TLS/SSL handshake with an TLS/SSL server
9 #include <openssl/ssl.h>
11 int SSL_connect(SSL *ssl);
15 SSL_connect() initiates the TLS/SSL handshake with a server. The communication
16 channel must already have been set and assigned to the B<ssl> by setting an
21 The behaviour of SSL_connect() depends on the underlying BIO.
23 If the underlying BIO is B<blocking>, SSL_connect() will only return once the
24 handshake has been finished or an error occurred.
26 If the underlying BIO is B<non-blocking>, SSL_connect() will also return
27 when the underlying BIO could not satisfy the needs of SSL_connect()
28 to continue the handshake, indicating the problem by the return value -1.
29 In this case a call to SSL_get_error() with the
30 return value of SSL_connect() will yield B<SSL_ERROR_WANT_READ> or
31 B<SSL_ERROR_WANT_WRITE>. The calling process then must repeat the call after
32 taking appropriate action to satisfy the needs of SSL_connect().
33 The action depends on the underlying BIO. When using a non-blocking socket,
34 nothing is to be done, but select() can be used to check for the required
35 condition. When using a buffering BIO, like a BIO pair, data must be written
36 into or retrieved out of the BIO before being able to continue.
40 The following return values can occur:
46 The TLS/SSL handshake was not successful but was shut down controlled and
47 by the specifications of the TLS/SSL protocol. Call SSL_get_error() with the
48 return value B<ret> to find out the reason.
52 The TLS/SSL handshake was successfully completed, a TLS/SSL connection has been
57 The TLS/SSL handshake was not successful, because a fatal error occurred either
58 at the protocol level or a connection failure occurred. The shutdown was
59 not clean. It can also occur of action is need to continue the operation
60 for non-blocking BIOs. Call SSL_get_error() with the return value B<ret>
61 to find out the reason.
67 L<SSL_get_error(3)>, L<SSL_accept(3)>,
68 L<SSL_shutdown(3)>, L<ssl(3)>, L<bio(3)>,
69 L<SSL_set_connect_state(3)>,
70 L<SSL_do_handshake(3)>,
75 Copyright 2000-2016 The OpenSSL Project Authors. All Rights Reserved.
77 Licensed under the OpenSSL license (the "License"). You may not use
78 this file except in compliance with the License. You can obtain a copy
79 in the file LICENSE in the source distribution or at
80 L<https://www.openssl.org/source/license.html>.