typedef struct a_server_context {
    void (SQL_CALLBACK *set_error)( a_server_context  *this
                                   , a_sql_uint32     error_code
                                   , const char       *error_string
                                   , short            error_string_length
                                  );
    a_sql_uint32 (SQL_CALLBACK *get_is_cancelled)( a_server_context *this
                                    );
    void (SQL_CALLBACK *log_message)( a_server_context *this
                                    , const char       *message_string
                                    , short            message_string_length
                                    );
    void *_context;
} a_server_context, *p_server_context;