=pod =head1 NAME SSL_connect - initiate the TLS/SSL handshake with an TLS/SSL server =head1 SYNOPSIS #include <openssl/ssl.h> int SSL_connect(SSL *ssl); =head1 DESCRIPTION SSL_connect() initiates the TLS/SSL handshake with a server. The communication channel must already have been set and assigned to the B<ssl> by setting an underlying B<BIO>. =head1 NOTES The behaviour of SSL_connect() depends on the underlying BIO. If the underlying BIO is B<blocking>, SSL_connect() will only return once the handshake has been finished or an error occurred. If the underlying BIO is B<non-blocking>, SSL_connect() will also return when the underlying BIO could not satisfy the needs of SSL_connect() to continue the handshake, indicating the problem by the return value -1. In this case a call to SSL_get_error() with the return value of SSL_connect() will yield B<SSL_ERROR_WANT_READ> or B<SSL_ERROR_WANT_WRITE>. The calling process then must repeat the call after taking appropriate action to satisfy the needs of SSL_connect(). The action depends on the underlying BIO. When using a non-blocking socket, nothing is to be done, but select() can be used to check 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 RETURN VALUES The following return values can occur: =over 4 =item 1 The TLS/SSL handshake was successfully completed, a TLS/SSL connection has been established. =item 0 The TLS/SSL handshake was not successful but was shut down controlled and by the specifications of the TLS/SSL protocol. Call SSL_get_error() with the return value B<ret> to find out the reason. =item E<lt>0 The TLS/SSL handshake was not successful, because a fatal error occurred either at the protocol level or a connection failure occurred. The shutdown was not clean. It can also occur of action is need to continue the operation for non-blocking BIOs. Call SSL_get_error() with the return value B<ret> to find out the reason. =back =head1 SEE ALSO L<SSL_get_error(3)|SSL_get_error(3)>, L<SSL_accept(3)|SSL_accept(3)>, L<SSL_shutdown(3)|SSL_shutdown(3)>, L<ssl(3)|ssl(3)>, L<bio(3)|bio(3)>, L<SSL_set_connect_state(3)|SSL_set_connect_state(3)>, L<SSL_do_handshake(3)|SSL_do_handshake(3)>, L<SSL_CTX_new(3)|SSL_CTX_new(3)> =cut