xcb_send_event (3) - Linux Manuals

xcb_send_event: send an event


xcb_send_event - send an event


#include <xcb/xproto.h>

Request function

xcb_void_cookie_t xcb_send_event(xcb_connection_t *conn, uint8_t propagate, xcb_window_t destination, uint32_t event_mask, const char *event);


The XCB connection to X11.
If propagate is true and no clients have selected any event on destination, the destination is replaced with the closest ancestor of destination for which some client has selected a type in event_mask and for which no intervening window has that type in its do-not-propagate-mask. If no such window exists or if the window is an ancestor of the focus window and InputFocus was originally specified as the destination, the event is not sent to any clients. Otherwise, the event is reported to every client selecting on the final destination any of the types specified in event_mask.
The window to send this event to. Every client which selects any event within event_mask on destination will get the event.

The special value XCB_SEND_EVENT_DEST_POINTER_WINDOW refers to the window that contains the mouse pointer.

The special value XCB_SEND_EVENT_DEST_ITEM_FOCUS refers to the window which has the keyboard focus.

Event_mask for determining which clients should receive the specified event. See destination and propagate.
The event to send to the specified destination.


Identifies the destination window, determines which clients should receive the specified event and ignores any active grabs.

The event must be one of the core events or an event defined by an extension, so that the X server can correctly byte-swap the contents as necessary. The contents of event are otherwise unaltered and unchecked except for the send_event field which is forced to 'true'.


Returns an xcb_void_cookie_t. Errors (if any) have to be handled in the event loop.

If you want to handle errors directly with xcb_request_check instead, use xcb_send_event_checked. See xcb-requests(3) for details.


The given event is neither a core event nor an event defined by an extension.
The specified destination window does not exist.


 * Tell the given window that it was configured to a size of 800x600 pixels.
void my_example(xcb_connection_t *conn, xcb_window_t window) {
    /* Every X11 event is 32 bytes long. Therefore, XCB will copy 32 bytes.
     * In order to properly initialize these bytes, we allocate 32 bytes even
     * though we only need less for an xcb_configure_notify_event_t */
    xcb_configure_notify_event_t *event = calloc(32, 1);

    event->event = window;
    event->window = window;
    event->response_type = XCB_CONFIGURE_NOTIFY;

    event->x = 0;
    event->y = 0;
    event->width = 800;
    event->height = 600;

    event->border_width = 0;
    event->above_sibling = XCB_NONE;
    event->override_redirect = false;

    xcb_send_event(conn, false, window, XCB_EVENT_MASK_STRUCTURE_NOTIFY,


Generated from xproto.xml. Contact xcb [at] lists.freedesktop.org for corrections and improvements.