XSendExtensionEvent man page
XSendExtensionEvent — send input extension events to a client
Status XSendExtensionEvent( Display *display, XDevice *device, Window destination, Bool propagate, int event_count, XEventClass *event_list, XEvent *event_send);
display Specifies the connection to the X server.
device Specifies the device from which the events are to be sent.
destination Specifies the window the event is to be sent to. You can pass window id, PointerWindow,or InputFocus.
propagate Specifies a Boolean value that is either True or False.
event_count Specifies the count of XEventClasses in event_list.
event_list Specifies the list of event selections to be used.
event_send Specifies a pointer to the event that is to be sent.
The XSendExtensionEvent request identifies the destination window, determines which clients should receive the specified events, and ignores any active grabs. This request requires you to pass an event class list. For a discussion of the valid event class names, see XOpenDevice(3) This request uses the w argument to identify the destination window as follows: * If w is PointerWindow,the destination window is the window that contains the pointer. * If w is InputFocusand if the focus window contains the pointer,the destination window is the window that contains the pointer; otherwise, the destination window is the focus window.
To determine which clients should receive the specified events, XSendExtensionEventuses the propagate argument as follows: * If event_list is the empty set,the event is sent to the client that created the destination window. If that client no longer exists,no event is sent. * If propagate is False,the event is sent to every client selecting on destination any of the eventtypes specified by the event_list array. * If propagate is Trueand no clients have selected on destination any ofthe events specified by the event_list array,the destination is replaced with theclosest ancestor of destination for which some client has selected atype specified by the event-list array and for which no interveningwindow has that type in itsdo-not-propagate-mask. If no such window exists or if the window isan ancestor of the focus window and InputFocuswas originally specifiedas the destination, the event is not sent to any clients. Otherwise, the event is reported to every client selecting on the finaldestination any of the events specified in the event_list array.
The event in the XEventstructure must be one of the events defined by the input extension (or a BadValueerror results) so that the X server can correctly byte-swapthe contents as necessary. The contents of the event areotherwise unaltered and unchecked by the X server except to force send_event to Truein the forwarded event and to set the serial number in the event correctly.
XSendExtensionEventreturns zero if the conversion to wire protocol format failedand returns nonzero otherwise.XSendExtensionEventcan generate BadClass, BadDevice, BadValue, and BadWindow errors.
BadDevice An invalid device was specified. The specified device does not exist or has not been opened by this client via XOpenInputDevice. This error may also occur if the specified device is the X keyboard or X pointer device.
BadValue Some numeric value falls outside the range of values accepted by the request. Unless a specific range is specified for an argument, the full range defined by the argument's type is accepted. Any argument defined as a set of alternatives can generate this error.
BadWindow A value for a Window argument does not name a defined window.