+/**
+ * @brief Send a file descriptor to the server in the next call to xcb_send_request.
+ * @param c: The connection to the X server.
+ * @param fd: The file descriptor to send.
+ *
+ * After this function returns, the file descriptor given is owned by xcb and
+ * will be closed eventually.
+ *
+ * FIXME: How the heck is this supposed to work in a thread-safe way? There is a
+ * race between two threads doing xcb_send_fd(); xcb_send_request(); at the same
+ * time.
+ */
+void xcb_send_fd(xcb_connection_t *c, int fd);
+
+/**
+ * @brief Take over the write side of the socket
+ * @param c: The connection to the X server.
+ * @param return_socket: Callback function that will be called when xcb wants
+ * to use the socket again.
+ * @param closure: Argument to the callback function.
+ * @param flags: A combination of flags from the xcb_send_request_flags_t enumeration.
+ * @param sent: Location to the sequence number of the last sequence request.
+ * Must not be NULL.
+ * @return 1 on success, else 0.
+ *
+ * xcb_take_socket allows external code to ask XCB for permission to
+ * take over the write side of the socket and send raw data with
+ * xcb_writev. xcb_take_socket provides the sequence number of the last
+ * request XCB sent. The caller of xcb_take_socket must supply a
+ * callback which XCB can call when it wants the write side of the
+ * socket back to make a request. This callback synchronizes with the
+ * external socket owner and flushes any output queues if appropriate.
+ * If you are sending requests which won't cause a reply, please note the
+ * comment for xcb_writev which explains some sequence number wrap issues.
+ *
+ * All replies that are generated while the socket is owned externally have
+ * @p flags applied to them. For example, use XCB_REQUEST_CHECK if you don't
+ * want errors to go to xcb's normal error handling, but instead having to be
+ * picked up via xcb_wait_for_reply(), xcb_poll_for_reply() or
+ * xcb_request_check().
+ */
+int xcb_take_socket(xcb_connection_t *c, void (*return_socket)(void *closure), void *closure, int flags, uint64_t *sent);
+
+/**
+ * @brief Send raw data to the X server.
+ * @param c: The connection to the X server.
+ * @param vector: Array of data to be sent.
+ * @param count: Number of entries in @p vector.
+ * @param requests: Number of requests that are being sent.
+ * @return 1 on success, else 0.
+ *
+ * You must own the write-side of the socket (you've called
+ * xcb_take_socket, and haven't returned from return_socket yet) to call
+ * xcb_writev. Also, the iovec must have at least 1 byte of data in it.
+ * You have to make sure that xcb can detect sequence number wraps correctly.
+ * This means that the first request you send after xcb_take_socket must cause a
+ * reply (e.g. just insert a GetInputFocus request). After every (1 << 16) - 1
+ * requests without a reply, you have to insert a request which will cause a
+ * reply. You can again use GetInputFocus for this. You do not have to wait for
+ * any of the GetInputFocus replies, but can instead handle them via
+ * xcb_discard_reply().
+ */
+int xcb_writev(xcb_connection_t *c, struct iovec *vector, int count, uint64_t requests);