<HTML>
<HEAD>
<TITLE>XtAppAddSignal</TITLE>
</HEAD>
<BODY>
<PRE>



XtAppAddSignal(3Xt)		XT FUNCTIONS		  XtAppAddSignal(3Xt)



NAME
  XtAppAddSignal, XtRemoveSignal, XtNoticeSignal - register and remove a sig-
  nal source

SYNTAX
  XtSignalId XtAppAddSignal(app_context, proc, client_data)
	XtAppContext app_context;
	XtInputCallbackProc proc;
	XtPointer client_data;

  void XtRemoveSignal(id)
	XtSignalId id;

  void XtNoticeSignal(id)
	XtSignalId id)

ARGUMENTS

  app_context
	    Specifies the application context.

  client_data
	    Specifies the argument that is to be passed to the specified pro-
	    cedure when a signal has been raised.

  id	    Specifies the ID returned from the corresponding XtAppAddSignal
	    call.

  proc	    Specifies the procedure that is to be called when the signal has
	    been raised.

DESCRIPTION
  The XtAppAddSignal function initiates a mechanism for handling sig-
  nals within the context of the Intrinsics. Prior to establishing an operat-
  ing system dependent signal handler the application may call XtAppAddSig-
  nalHandler and store the returned id in a place accessible to the signal
  handler.

  Upon receipt of a signal from the operating system, the application may
  call XtNoticeSignal passing the id returned by the call to XtAppAddSignal.

  XtNoticeSignal is the only Intrinsics function that can safely be called
  from a signal handler. If XtNoticeSignal is called multiple times before
  the Intrinsics are able to invoke the registered callback, the callback is
  only called once. Logically the Intrinsics maintain ``pending'' for each
  registered callback. This flag is initially False and is set to True by
  XtNoticeSignal; the Intrinsics invoke the callback whenever the flag is
  True, and the flag is set to False just before the callback is invoked.

  The XtRemoveSignal function is called to remove the specified Intrinsics
  signal handler. The client should disable the source of the signal before
  calling XtRemoveSignal.

SEE ALSO
  XtAppAddTimeOut(3Xt),XtAppAddInput(3Xt),XtAppAddWorkProc(3Xt)
  X Toolkit Intrinsics - C Language Interface
  Xlib - C Language X Interface


</PRE>
</BODY>
</HTML>
