Provided by: libx11-doc_1.7.5-1ubuntu0.3_all 
NAME
XAnyEvent, XEvent - generic X event structures
STRUCTURES
All the event structures declared in <X11/Xlib.h> have the following common members:
typedef struct {
int type;
unsigned long serial; /* # of last request processed by server */
Bool send_event; /* true if this came from a SendEvent request */
Display *display; /* Display the event was read from */
Window window;
} XAnyEvent;
The type member is set to the event type constant name that uniquely identifies it. For example, when
the X server reports a GraphicsExpose event to a client application, it sends an XGraphicsExposeEvent
structure with the type member set to GraphicsExpose. The display member is set to a pointer to the
display the event was read on. The send_event member is set to True if the event came from a SendEvent
protocol request. The serial member is set from the serial number reported in the protocol but expanded
from the 16-bit least-significant bits to a full 32-bit value. The window member is set to the window
that is most useful to toolkit dispatchers.
The XEvent structure is a union of the individual structures declared for each event type:
typedef union _XEvent {
int type; /* must not be changed */
XAnyEvent xany;
XKeyEvent xkey;
XButtonEvent xbutton;
XMotionEvent xmotion;
XCrossingEvent xcrossing;
XFocusChangeEvent xfocus;
XExposeEvent xexpose;
XGraphicsExposeEvent xgraphicsexpose;
XNoExposeEvent xnoexpose;
XVisibilityEvent xvisibility;
XCreateWindowEvent xcreatewindow;
XDestroyWindowEvent xdestroywindow;
XUnmapEvent xunmap;
XMapEvent xmap;
XMapRequestEvent xmaprequest;
XReparentEvent xreparent;
XConfigureEvent xconfigure;
XGravityEvent xgravity;
XResizeRequestEvent xresizerequest;
XConfigureRequestEvent xconfigurerequest;
XCirculateEvent xcirculate;
XCirculateRequestEvent xcirculaterequest;
XPropertyEvent xproperty;
XSelectionClearEvent xselectionclear;
XSelectionRequestEvent xselectionrequest;
XSelectionEvent xselection;
XColormapEvent xcolormap;
XClientMessageEvent xclient;
XMappingEvent xmapping;
XErrorEvent xerror;
XKeymapEvent xkeymap;
long pad[24];
} XEvent;
An XEvent structure's first entry always is the type member, which is set to the event type. The second
member always is the serial number of the protocol request that generated the event. The third member
always is send_event, which is a Bool that indicates if the event was sent by a different client. The
fourth member always is a display, which is the display that the event was read from. Except for keymap
events, the fifth member always is a window, which has been carefully selected to be useful to toolkit
dispatchers. To avoid breaking toolkits, the order of these first five entries is not to change. Most
events also contain a time member, which is the time at which an event occurred. In addition, a pointer
to the generic event must be cast before it is used to access any other information in the structure.
SEE ALSO
XButtonEvent(3), XCreateWindowEvent(3), XCirculateEvent(3), XCirculateRequestEvent(3), XColormapEvent(3), XConfigureEvent(3), XConfigureRequestEvent(3), XCrossingEvent(3), XDestroyWindowEvent(3), XErrorEvent(3), XExposeEvent(3), XFocusChangeEvent(3), XGraphicsExposeEvent(3), XGravityEvent(3), XKeymapEvent(3), XMapEvent(3), XMapRequestEvent(3), XPropertyEvent(3), XReparentEvent(3), XResizeRequestEvent(3), XSelectionClearEvent(3), XSelectionEvent(3), XSelectionRequestEvent(3), XUnmapEvent(3), XVisibilityEvent(3) Xlib - C Language X Interface