SSL_connect(3)

SSL_connect(3)               OpenSSL               SSL_connect(3)

NAME

     SSL_connect - initiate the TLS/SSL handshake with an TLS/SSL
     server

SYNOPSIS

      #include <openssl/ssl.h>

      int SSL_connect(SSL *ssl);

DESCRIPTION

     SSL_connect() initiates the TLS/SSL handshake with a server.
     The communication channel must already have been set and
     assigned to the ssl by setting an underlying BIO.

NOTES

     The behaviour of SSL_connect() depends on the underlying
     BIO.

     If the underlying BIO is blocking, SSL_connect() will only
     return once the handshake has been finished or an error
     occurred.

     If the underlying BIO is 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 SSL_ERROR_WANT_READ or 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.

RETURN VALUES

     The following return values can occur:

     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 ret
         to find out the reason.

     1   The TLS/SSL handshake was successfully completed, a
         TLS/SSL connection has been established.

     <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()

1.0.2t               Last change: 2019-09-10                    1

SSL_connect(3)               OpenSSL               SSL_connect(3)

         with the return value ret to find out the reason.

SEE ALSO

     SSL_get_error(3), SSL_accept(3), SSL_shutdown(3), ssl(3),
     bio(3), SSL_set_connect_state(3), SSL_do_handshake(3),
     SSL_CTX_new(3)

1.0.2t               Last change: 2019-09-10                    2