XLIB Programming Manual, Rel. 5, Third Edition

Name

EnterNotify,LeaveNotify — xcrossing

When Generated

EnterNotify and LeaveNotify events occur when the pointer enters or leaves a window.

When the pointer crosses a window border, a LeaveNotify event occurs in the window being left and an EnterNotify event occurs in the window being entered. Whether or not each event is queued for any application depends on whether any application selected the right event on the window in which it occurred.

In addition, EnterNotify and LeaveNotify events are delivered to windows that are virtually crossed. These are windows that are between the origin and destination windows in the hierarchy but not necessarily on the screen. Further explanation of virtual crossing is provided two pages following.

Select With

Each of these events can be selected separately with XEnterWindowMask and XLeaveWindowMask.

XEvent Structure Name

typedef union _XEvent {
    ...
    XCrossingEvent xcrossing;
    ...
} XEvent;

Event Structure

typedef struct { int type; /* of event */ unsigned long serial; /* # of last request processed by server */ Bool send_event; /* True if this came from SendEvent request */ Display *display; /* Display the event was read from */ Window window; /* event window it is reported relative to */ Window root; /* root window that the event occurred on */ Window subwindow; /* child window */ Time time; /* milliseconds */ int x, y; /* pointer x,y coordinates in receiving * window */ int x_root, y_root; /* coordinates relative to root */ int mode; /* NotifyNormal, NotifyGrab, ...