XNextEvent(3X)                                     XNextEvent(3X)



NAME
     XNextEvent, XPeekEvent, XWindowEvent, XCheckWindowEvent,
     XMaskEvent, XCheckMaskEvent, XCheckTypedEvent,
     XCheckTypedWindowEvent - select events by type

SYNOPSIS
     XNextEvent(display, event-return)
     Display *display;
     XEvent *event-return;

     XPeekEvent(display, event-return)
     Display *display;
     XEvent *event-return;

     XWindowEvent(display, w, event-mask, event-return)
     Display *display;
     Window w;
     long event-mask;
     XEvent *event-return;

     Bool XCheckWindowEvent(display, w, event-mask, event-return)
     Display *display;
     Window w;
     long event-mask;
     XEvent *event-return;

     XMaskEvent(display, event-mask, event-return)
     Display *display;
     long event-mask;
     XEvent *event-return;

     Bool XCheckMaskEvent(display, event-mask, event-return)
     Display *display;
     long event-mask;
     XEvent *event-return;

     Bool XCheckTypedEvent(display, event-type, event-return)
     Display *display;
     int event-type;
     XEvent *event-return;

     Bool XCheckTypedWindowEvent(display, w, event-type, event-
     return)
     Display *display;
     Window w;
     int event-type;
     XEvent *event-return;

DESCRIPTION
     The XNextEvent function copies the first event from the
     event queue into the specified XEvent structure and then re-
     moves it from the queue.  If the event queue is empty, XNex-



November, 1990                                                  1

XNextEvent(3X)                                     XNextEvent(3X)



     tEvent flushes the output buffer and blocks until an event
     is received.

     The XPeekEvent function returns the first event from the
     event queue, but it does not remove the event from the
     queue.  If the queue is empty, XPeekEvent flushes the output
     buffer and blocks until an event is received.  It then
     copies the event into the client-supplied XEvent structure
     without removing it from the event queue.

     The XWindowEvent function searches the event queue for an
     event that matches both the specified window and event mask.
     When it finds a match, XWindowEvent removes that event from
     the queue and copies it into the specified XEvent structure.
     The other events stored in the queue are not discarded.  If
     a matching event is not in the queue, XWindowEvent flushes
     the output buffer and blocks until one is received.

     The XCheckWindowEvent function searches the event queue and
     then the events available on the server connection for the
     first event that matches the specified window and event
     mask.  If it finds a match, XCheckWindowEvent removes that
     event, copies it into the specified XEvent structure, and
     returns TRUE.  The other events stored in the queue are not
     discarded.  If the event you requested is not available,
     XCheckWindowEvent returns FALSE, and the output buffer is
     flushed.

     The XMaskEvent function searches the event queue for the
     events associated with the specified mask.  When it finds a
     match, XMaskEvent removes that event and copies it into the
     specified XEvent structure.  The other events stored in the
     queue are not discarded.  If the event you requested is not
     in the queue, XMaskEvent flushes the output buffer and
     blocks until one is received.

     The XCheckMaskEvent function searches the event queue and
     then any events available on the server connection for the
     first event that matches the specified mask.  If it finds a
     match, XCheckMaskEvent removes that event, copies it into
     the specified XEvent structure, and returns TRUE.  The other
     events stored in the queue are not discarded.  If the event
     you requested is not available, XCheckMaskEvent returns
     FALSE, and the output buffer is flushed.

     The XCheckTypedEvent function searches the event queue and
     then any events available on the server connection for the
     first event that matches the specified type.  If it finds a
     match, XCheckTypedEvent removes that event, copies it into
     the specified XEvent structure, and returns TRUE.  The other
     events in the queue are not discarded.  If the event is not
     available, XCheckTypedEvent returns FALSE, and the output



2                                                  November, 1990

XNextEvent(3X)                                     XNextEvent(3X)



     buffer is flushed.

     The XCheckTypedWindowEvent function searches the event queue
     and then any events available on the server connection for
     the first event that matches the specified type and window.
     If it finds a match, XCheckTypedWindowEvent removes the
     event from the queue, copies it into the specified XEvent
     structure, and returns TRUE.  The other events in the queue
     are not discarded.  If the event is not available, XCheck-
     TypedWindowEvent returns FALSE, and the output buffer is
     flushed.

   Arguments
     These functions accept the following arguments:

     display Specifies the connection to the X server.

     event-mask
             Specifies the event mask.

     event-return
             Returns the matched event's associated structure,
             the next event in the queue, or a copy of the
             matched event's associated structure.

     event-type
             Specifies the event type to be compared.

     w       Specifies the window whose event you are interested
             in.

SEE ALSO
     XAnyEvent(3X), XIfEvent(3X), XPutBackEvent(3X),
     XSendEvent(3X)

     Xlib - C Language Interface




















November, 1990                                                  3