XCheckMaskEvent






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

int XNextEvent(Display *display, XEvent *event_return); int
XPeekEvent(Display *display, XEvent *event_return); int
XWindowEvent(Display *display, Window w, long event_mask,
XEvent *event_return); Bool XCheckWindowEvent(Display
*display, Window w, long event_mask, XEvent *event_return);
int XMaskEvent(Display *display, long event_mask, XEvent
*event_return); Bool XCheckMaskEvent(Display *display, long
event_mask, XEvent *event_return); Bool
XCheckTypedEvent(Display *display, int event_type, XEvent
*event_return); Bool XCheckTypedWindowEvent(Display
*display, Window w, int event_type, XEvent *event_return);



display   Specifies the connection to the X server.

event_mask
          Specifies the event mask.

event_return
          Returns the matched event’s associated structure.

event_return
          Returns the next event in the queue.

event_return
          Returns 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.

The XNextEvent function copies the first event from the
event queue into the specified XEvent structure and then
removes it from the queue.  If the event queue is empty,
XNextEvent 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.









                             ‐2‐


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 The other events stored in the queue are not
discarded.  If the event you requested is not available,
XCheckWindowEvent returns and the output buffer will have
been 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 The other events
stored in the queue are not discarded.  If the event you
requested is not available, XCheckMaskEvent returns and the
output buffer will have been 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 The other events
in the queue are not discarded.  If the event is not
available, XCheckTypedEvent returns and the output buffer
will have been 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 The other events in the queue are not
discarded.  If the event is not available,
XCheckTypedWindowEvent returns and the output buffer will
have been flushed.












                             ‐3‐


XAnyEvent(3), XIfEvent(3), XPutBackEvent(3), XSendEvent(3)
Xlib − C Language X Interface