HPUX RestrictEv[3]

 Tk_RestrictEvents(3)                Tk                 Tk_RestrictEvents(3)

 Tk Library Procedures                                 Tk Library Procedures





 ___________________________________________________________________________

 NAME
      Tk_RestrictEvents - filter and selectively delay X events

 SYNOPSIS
      #include <tk.h>

      Tk_RestrictProc *
      Tk_RestrictEvents(proc, arg, prevArgPtr)

 ARGUMENTS
      Tk_RestrictProc   *proc          (in)      Predicate procedure to call
                                                 to    filter   incoming   X
                                                 events.  NULL means do  not
                                                 restrict events at all.

      char              *arg           (in)      Arbitrary argument to  pass
                                                 to proc.

      char              **prevArgPtr   (in/out)  Pointer to  place  to  save
                                                 argument     to    previous
                                                 restrict procedure.
 ___________________________________________________________________________


 DESCRIPTION
      This procedure is useful in certain situations where applications  are
      only prepared to receive certain X events.  After Tk_RestrictEvents is
      called, Tk_DoOneEvent (and hence  Tk_MainLoop)  will  filter  X  input
      events  through  proc.   Proc indicates whether a given event is to be
      processed immediately or deferred until some later time (e.g. when the
      event  restriction  is  lifted).   Proc  is  a  standard  X  predicate
      procedure,  of  the  sort  passed  to  XCheckIfEvent.   It  must  have
      arguments and result that match the type Tk_RestrictProc:
           typedef Bool Tk_RestrictProc(
                Display *display,
                XEvent *eventPtr,
                char *arg);
      The display argument to proc is the display from  which  eventPtr  was
      received,  and  eventPtr  points to an event under consideration.  The
      arg argument is a copy of the arg passed to Tk_RestrictEvents;  it may
      be  used  to  provide proc with information it needs to filter events.
      Proc must return True or  False.   True  means  the  event  should  be
      processed  immediately  and  False  means  the  event  should  not  be
      processed now, but should be saved for some later time.

      Tk_RestrictEvents uses its  return  value  and  prevArgPtr  to  return
      information  about  the  current  event  restriction procedure (a NULL



                                    - 1 -        Formatted:  August 11, 1996






 Tk_RestrictEvents(3)                Tk                 Tk_RestrictEvents(3)

 Tk Library Procedures                                 Tk Library Procedures





      return value means there are currently no restrictions).  These values
      may be used to restore the previous restriction state when there is no
      longer any need for the current restriction.

      There are very few places where Tk_RestrictEvents is  needed.   Please
      use  it  only  where  it  is  absolutely  necessary.   If only a local
      restriction is needed, it can probably be  achieved  more  cleanly  by
      changing event-to-Tcl bindings or by calling Tk_DeleteEventHandler.


 KEYWORDS
      delay, event, filter, restriction








































                                    - 2 -        Formatted:  August 11, 1996