gnutls_handshake(3)                gnutls                gnutls_handshake(3)

NAME         top

       gnutls_handshake - API function

SYNOPSIS         top

       #include <gnutls/gnutls.h>

       int gnutls_handshake(gnutls_session_t session);

ARGUMENTS         top

       gnutls_session_t session
                   is a gnutls_session_t type.

DESCRIPTION         top

       This function does the handshake of the TLS/SSL protocol, and
       initializes the TLS connection.

       This function will fail if any problem is encountered, and will
       return a negative error code. In case of a client, if the client has
       asked to resume a session, but the server couldn't, then a full
       handshake will be performed.

       The non-fatal errors expected by this function are:
       the latter only in a case of rehandshake.

       The former two interrupt the handshake procedure due to the lower
       layer being interrupted, and the latter because of an alert that may
       be sent by a server (it is always a good idea to check any received
       alerts). On these errors call this function again, until it returns
       0; cf.  gnutls_record_get_direction() and gnutls_error_is_fatal(). In
       DTLS sessions the non-fatal error GNUTLS_E_LARGE_PACKET is also
       possible, and indicates that the MTU should be adjusted.

       If this function is called by a server after a rehandshake request
       may be returned.  Note that these are non fatal errors, only in the
       specific case of a rehandshake.  Their meaning is that the client
       rejected the rehandshake request or in the case of
       GNUTLS_E_GOT_APPLICATION_DATA it could also mean that some data were
       pending. A client may receive that error code if it initiates the
       handshake and the server doesn't agreed.

RETURNS         top

       GNUTLS_E_SUCCESS on success, otherwise a negative error code.

REPORTING BUGS         top

       Report bugs to <>.
       Home page:

COPYRIGHT         top

       Copyright © 2001-2018 Free Software Foundation, Inc., and others.
       Copying and distribution of this file, with or without modification,
       are permitted in any medium without royalty provided the copyright
       notice and this notice are preserved.

SEE ALSO         top

       The full documentation for gnutls is maintained as a Texinfo manual.
       If the /usr/share/doc/gnutls/ directory does not contain the HTML
       form visit 

COLOPHON         top

       This page is part of the GnuTLS (GnuTLS Transport Layer Security
       Library) project.  Information about the project can be found at 
       ⟨⟩.  If you have a bug report for this manual
       page, send it to  This page was obtained from the
       tarball gnutls-3.6.2.tar.xz fetched from
       ⟨⟩ on 2018-04-30.  If you discover
       any rendering problems in this HTML version of the page, or you
       believe there is a better or more up-to-date source for the page, or
       you have corrections or improvements to the information in this
       COLOPHON (which is not part of the original manual page), send a mail

gnutls                              3.6.2                gnutls_handshake(3)