xtapppending(3) [hpux man page]

XtAppPending()															    XtAppPending()

Name
  XtAppPending - determine whether any events are in an application's input queue.

Synopsis
  XtInputMask XtAppPending(app_context)
	 XtAppContext app_context;

Inputs
  app_context
	    Specifies the application context.

Returns
  An XtInputMask which indicates what kind of events, if any, are pending on app_context.

Description
  XtAppPending() returns a nonzero value if there are pending events from the X server, timer, or other input sources.

  The  return  value is a bit mask that is the OR of XtIMXEvent (an X event), XtIMTimer (a timer event-see XtAppAddTimeOut()), and XtIMAlter-
  nateInput (an alternate input event-see XtAppAddInput()).  As a convenience, the symbolic name XtIMAll is defined as the bitwise  inclusive
  OR  of all event types.  If no events are pending, XtAppPending() flushes the output buffers of each display in the application context and
  returns zero.  This call is the Intrinsics equivalent to the Xlib call XPending().

  XtAppPending() never blocks.

Usage
  Programs rarely need this much control over the event dispatching mechanism.	Most programs use XtAppMainLoop().

Structures
  The XtInputMask type and its possible values are defined as follows:

     typedef unsigned long    XtInputMask;

     #define XtIMXEvent 	     1
     #define XtIMTimer		     2
     #define XtIMAlternateInput      4
     #define XtIMAll (XtIMXEvent   XtIMTimer   XtIMAlternateInput)

See Also
  XtAppAddInput(1), XtAppAddTimeOut(1), XtAppMainLoop(1), XtAppNextEvent(1), XtAppPeekEvent(1), XtAppProcessEvent(1), XtDispatchEvent(1).

Xt - Event Handling														    XtAppPending()

XtAppNextEvent(3Xt)													       XtAppNextEvent(3Xt)

NAME

       XtAppNextEvent, XtAppPending, XtAppPeekEvent, XtAppProcessEvent, XtDispatchEvent, XtAppMainLoop - query and process events and input

SYNOPSIS

       void XtAppNextEvent(app_context, event_return)
	       XtAppContext app_context;
	       XEvent *event_return;

       Boolean XtAppPeekEvent(app_context, event_return)
	       XtAppContext app_context;
	       XEvent *event_return;

       XtInputMask XtAppPending(app_context)
	       XtAppContext app_context;

       void XtAppProcessEvent(app_context, mask)
	       XtAppContext app_context;
	       XtInputMask mask;

       Boolean XtDispatchEvent(event)
	       XEvent *event;

       void XtAppMainLoop(app_context)
	       XtAppContext app_context;

ARGUMENTS

       Specifies  the application context that identifies the application.  Specifies a pointer to the event structure that is to be dispatched to
       the appropriate event handler.  Returns the event information to the specified event structure.	Specifies what types of events to process.
       The mask is the bitwise inclusive OR of any combination of XtIMXEvent, XtIMTimer, XtIMAlternateInput, and XtIMSignal. As a convenience, the
       X Toolkit defines the symbolic name XtIMAll to be the bitwise inclusive OR of all event types.

DESCRIPTION

       If the X event queue is empty, XtAppNextEvent flushes the X output buffers of each Display in the application  context  and  waits  for	an
       event  while looking at the other input sources, timeout values, and signal handlers and calling any callback procedures triggered by them.
       This wait time can be used for background processing (see Section 7.8).

       If there is an event in the queue, XtAppPeekEvent fills in the event and returns  a  nonzero  value.  If  no  X	input  is  on  the  queue,
       XtAppPeekEvent  flushes	the output buffer and blocks until input is available (possibly calling some timeout callbacks in the process). If
       the input is an event, XtAppPeekEvent fills in the event and returns a nonzero value. Otherwise,  the  input  is  for  an  alternate  input
       source, and XtAppPeekEvent returns zero.

       The  XtAppPending  function  returns  a	nonzero value if there are events pending from the X server, timer pending, or other input sources
       pending. The value returned is a bit mask that is the OR of XtIMXEvent, XtIMTimer, XtIMAlternateInput, and XtIMSignal (see  XtAppProcessEv-
       ent). If there are no events pending, XtAppPending flushes the output buffer and returns zero.

       The  XtAppProcessEvent  function  processes  one timer, alternate input, signal source, or X event.  If there is nothing of the appropriate
       type to process, XtAppProcessEvent blocks until there is.  If there is more than one type of thing available to process,  it  is  undefined
       which  will  get  processed. Usually, this procedure is not called by client applications (see XtAppMainLoop).  XtAppProcessEvent processes
       timer events by calling any appropriate timer callbacks, alternate input by calling  any  appropriate  alternate  input	callbacks,  signal
       source by calling any appropriate signal callbacks, and X events by calling XtDispatchEvent.

       When  an  X  event is received, it is passed to XtDispatchEvent, which calls the appropriate event handlers and passes them the widget, the
       event, and client-specific data registered with each procedure.	If there are no handlers for that event registered, the event  is  ignored
       and the dispatcher simply returns. The order in which the handlers are called is undefined.

       The  XtDispatchEvent function sends those events to the event handler functions that have been previously registered with the dispatch rou-
       tine.  XtDispatchEvent returns True if it dispatched the event to some handler and False if it found no handler to dispatch the	event  to.
       The  most  common  use of XtDispatchEvent is to dispatch events acquired with the XtAppNextEvent procedure. However, it also can be used to
       dispatch user-constructed events.  XtDispatchEvent also is responsible for implementing the grab semantics for XtAddGrab.

       The XtAppMainLoop function first reads the next incoming X event by calling XtAppNextEvent and then it dispatches the event to  the  appro-
       priate registered procedure by calling XtDispatchEvent. This constitutes the main loop of X Toolkit applications, and, as such, it does not
       return. Applications are expected to exit in response to some user action. There is nothing special about XtAppMainLoop; it  is	simply	an
       infinite loop that calls XtAppNextEvent and then XtDispatchEvent.

       Applications  can  provide  their  own version of this loop, which tests some global termination flag or tests that the number of top-level
       widgets is larger than zero before circling back to the call to XtAppNextEvent.

SEE ALSO

       X Toolkit Intrinsics -- C Language Interface

       Xlib -- C Language X Interface

															       XtAppNextEvent(3Xt)