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gnutls_transport_set_pull_timeout_function(3) gnutls gnutls_transport_set_pull_timeout_function(3)


gnutls_transport_set_pull_timeout_function - API function


#include <gnutls/gnutls.h>

void gnutls_transport_set_pull_timeout_function(gnutls_session_t session, gnutls_pull_timeout_func func);


gnutls_session_t session
is a gnutls_session_t type.
gnutls_pull_timeout_func func
a callback function


This is the function where you set a function for gnutls to know whether data are ready to be received. It should wait for data a given time frame in milliseconds. The callback should return 0 on timeout, a positive number if data can be received, and -1 on error. You'll need to override this function if select() is not suitable for the provided transport calls.

As with select(), if the timeout value is zero the callback should return zero if no data are immediately available. The special value GNUTLS_INDEFINITE_TIMEOUT indicates that the callback should wait indefinitely for data.

gnutls_pull_timeout_func is of the form, int (*gnutls_pull_timeout_func)(gnutls_transport_ptr_t, unsigned int ms);

This callback is necessary when gnutls_handshake_set_timeout() or gnutls_record_set_timeout() are set, and for calculating the DTLS mode timeouts.

In short, this callback should be set when a custom pull function is registered. The callback will not be used when the session is in TLS mode with non-blocking sockets. That is, when GNUTLS_NONBLOCK is specified for a TLS session in gnutls_init(). For compatibility with future GnuTLS versions it is recommended to always set this function when a custom pull function is registered.

The helper function gnutls_system_recv_timeout() is provided to simplify writing callbacks.




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