SSL_connect.pod revision 76866
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. In this case a call to SSL_get_error() with the 29return value of SSL_connect() will yield B<SSL_ERROR_WANT_READ> or 30B<SSL_ERROR_WANT_WRITE>. The calling process then must repeat the call after 31taking appropriate action to satisfy the needs of SSL_connect(). 32The action depends on the underlying BIO. When using a non-blocking socket, 33nothing is to be done, but select() can be used to check for the required 34condition. When using a buffering BIO, like a BIO pair, data must be written 35into or retrieved out of the BIO before being able to continue. 36 37When using a generic method (see L<SSL_CTX_new(3)|SSL_CTX_new(3)>), it 38is necessary to call L<SSL_set_connect_state(3)|SSL_set_connect_state(3)> 39before calling SSL_connect() to explicitly switch the B<ssl> to client 40mode. 41 42=head1 RETURN VALUES 43 44The following return values can occur: 45 46=over 4 47 48=item 1 49 50The TLS/SSL handshake was successfully completed, a TLS/SSL connection has been 51established. 52 53=item 0 54 55The TLS/SSL handshake was not successful but was shut down controlled and 56by the specifications of the TLS/SSL protocol. Call SSL_get_error() with the 57return value B<ret> to find out the reason. 58 59=item E<lt>0 60 61The TLS/SSL handshake was not successful, because a fatal error occurred either 62at the protocol level or a connection failure occurred. The shutdown was 63not clean. It can also occur of action is need to continue the operation 64for non-blocking BIOs. Call SSL_get_error() with the return value B<ret> 65to find out the reason. 66 67=back 68 69=head1 SEE ALSO 70 71L<SSL_get_error(3)|SSL_get_error(3)>, L<SSL_accept(3)|SSL_accept(3)>, 72L<SSL_shutdown(3)|SSL_shutdown(3)>, L<ssl(3)|ssl(3)>, L<bio(3)|bio(3)>, 73L<SSL_set_connect_state(3)|SSL_set_connect_state(3)>, 74L<SSL_CTX_new(3)|SSL_CTX_new(3)> 75 76=cut 77