#include <sasl/sasl.h>
int sasl_encode(sasl_conn_t *conn, 
                    const char * input, 
                    unsigned inputlen, 
                    const char ** output, 
                    unsigned * outputlen);
int sasl_encodev(sasl_conn_t *conn, 
                    const struct iovec * invec, 
                    unsigned numiov, 
                    const char ** output, 
                    unsigned * outputlen);
 
sasl_encode encodes data to be sent to be sent to a remote host who we've had a successful authentication session with. If there is a negotiated security the data in signed/encrypted and the output should be sent without modification to the remote host. If there is no security layer the output is identical to the input.
sasl_encodev does the same, but for a struct iovec instead of a character buffer.
output contains the encoded data and is allocated/freed by the library.