gnutls_handshake(3)

NAME
gnutls_handshake - API function

SYNOPSIS
#include <gnutls/gnutls.h>

int gnutls_handshake(gnutls_session_t session);

ARGUMENTS

gnutls_session_t session
    is a gnutls_session_t type.

DESCRIPTION
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: GNUTLS_E_INTERRUPTED, GNUTLS_E_AGAIN, GNUTLS_E_WARNING_ALERT_RECEIVED, and GNUTLS_E_GOT_APPLICATION_DATA, 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 then GNUTLS_E_GOT_APPLICATION_DATA or GNUTLS_E_WARNING_ALERT_RECEIVED 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
GNUTLS_E_SUCCESS on success, otherwise a negative error code.

REPORTING BUGS
Report bugs to <bugs@gnutls.org>.
Home page: http://www.gnutls.org

COPYRIGHT
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
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

http://www.gnutls.org/manual/