+xcb_generic_event_t *xcb_poll_for_queued_event(xcb_connection_t *c);
+
+/**
+ * @brief Return the error for a request, or NULL if none can ever arrive.
+ * @param c: The connection to the X server.
+ * @param cookie: The request cookie.
+ * @return The error for the request, or NULL if none can ever arrive.
+ *
+ * The xcb_void_cookie_t cookie supplied to this function must have resulted
+ * from a call to xcb_[request_name]_checked(). This function will block
+ * until one of two conditions happens. If an error is received, it will be
+ * returned. If a reply to a subsequent request has already arrived, no error
+ * can arrive for this request, so this function will return NULL.
+ *
+ * Note that this function will perform a sync if needed to ensure that the
+ * sequence number will advance beyond that provided in cookie; this is a
+ * convenience to avoid races in determining whether the sync is needed.
+ */
+xcb_generic_error_t *xcb_request_check(xcb_connection_t *c, xcb_void_cookie_t cookie);
+
+/**
+ * @brief Discards the reply for a request.
+ * @param c: The connection to the X server.
+ * @param sequence: The request sequence number from a cookie.
+ *
+ * Discards the reply for a request. Additionally, any error generated
+ * by the request is also discarded (unless it was an _unchecked request
+ * and the error has already arrived).
+ *
+ * This function will not block even if the reply is not yet available.
+ *
+ * Note that the sequence really does have to come from an xcb cookie;
+ * this function is not designed to operate on socket-handoff replies.
+ */
+void xcb_discard_reply(xcb_connection_t *c, unsigned int sequence);