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XkbForceBell(3)			 XKB FUNCTIONS		       XkbForceBell(3)

       XkbForceBell  - Overrides user preference settings for audible bells to
       ring the	bell on	the default keyboard

       Bool XkbForceBell (Display *display, int	percent);

       - display
	      connection to the	X server

       - percent
	      volume for the bell, which can range from	-100 to	100 inclusive

       The core	X protocol allows only applications to	explicitly  sound  the
       system  bell with a given duration, pitch, and volume. Xkb extends this
       capability by allowing clients to attach	symbolic names to bells,  dis-
       able  audible bells, and	receive	an event whenever the keyboard bell is
       rung. For the purposes of this document,	the audible bell is defined to
       be  the	system	bell,  or the default keyboard bell, as	opposed	to any
       other audible sound generated elsewhere in the system.  You can ask  to
       receive	XkbBellNotify events when any client rings any one of the fol-

       o    The	default	bell

       o    Any	bell on	an input device	that can be specified by a  bell_class
	    and	bell_id	pair

       o    Any	 bell  specified only by an arbitrary name. (This is, from the
	    server's point of view, merely a name, and not connected with  any
	    physical  sound-generating	device.	 Some  client application must
	    generate the sound,	or visual feedback, if any, that is associated
	    with the name.)

       You  can	also ask to receive XkbBellNotify events when the server rings
       the default bell	or if any client has requested	events	only  (without
       the bell	sounding) for any of the bell types previously listed.

       You  can	disable	audible	bells on a global basis. For example, a	client
       that replaces the keyboard bell with some other audible cue might  want
       to  turn	 off  the  AudibleBell control to prevent the server from also
       generating a sound and avoid cacophony. If you  disable	audible	 bells
       and  request to receive XkbBellNotify events, you can generate feedback
       different from the default bell.

       You can,	however, override the AudibleBell control by  calling  one  of
       the  functions that force the ringing of	a bell in spite	of the setting
       of the AudibleBell control - XkbForceDeviceBell	or  XkbForceBell.   In
       this case the server does not generate a	bell event.

       Just  as	some keyboards can produce keyclicks to	indicate when a	key is
       pressed or repeating, Xkb can provide feedback for the controls by  us-
       ing special beep	codes.	The AccessXFeedback control is used to config-
       ure the specific	types of operations that generate feedback.

       Bell Names

       You can associate a name	to an act of ringing a bell by converting  the
       name  to	 an  Atom and then using this name when	you call the functions
       listed in this chapter. If an event is generated	as a result, the  name
       is  then	passed to all other clients interested in receiving XkbBellNo-
       tify events. Note that these are	arbitrary names	and that there	is  no
       binding	to  any	 sounds.  Any  sounds or other effects (such as	visual
       bells on	the screen) must be generated by a client application upon re-
       ceipt  of  the bell event containing the	name. There is no default name
       for the default keyboard	bell. The server does generate some predefined
       bells  for the AccessX controls.	These named bells are shown in the Ta-
       ble 1; the name is included in any bell event sent to clients that have
       requested to receive XkbBellNotify events.

			 Table 1 Predefined Bells
       Action					  Named	Bell
       Indicator turned	on			  AX_IndicatorOn
       Indicator turned	off			  AX_IndicatorOff
       More than one indicator changed state	  AX_IndicatorChange
       Control turned on			  AX_FeatureOn
       Control turned off			  AX_FeatureOff
       More than one control changed state	  AX_FeatureChange
       SlowKeys	 and  BounceKeys  about	 to  be	  AX_SlowKeysWarning
       turned on or off
       SlowKeys	key pressed			  AX_SlowKeyPress
       SlowKeys	key accepted			  AX_SlowKeyAccept
       SlowKeys	key rejected			  AX_SlowKeyReject
       Accepted	SlowKeys key released		  AX_SlowKeyRelease
       BounceKeys key rejected			  AX_BounceKeyReject
       StickyKeys key latched			  AX_StickyLatch
       StickyKeys key locked			  AX_StickyLock
       StickyKeys key unlocked			  AX_StickyUnlock

       Audible Bells

       Using Xkb you can generate bell events that do not necessarily ring the
       system bell.  This is useful if you need	to use an audio	server instead
       of the system beep. For example,	when an	audio client starts, it	 could
       disable the audible bell	(the system bell) and then listen for XkbBell-
       Notify events. When it receives a XkbBellNotify event, the audio	client
       could then send a request to an audio server to play a sound.

       You  can	 control  the audible bells feature by passing the XkbAudible-
       BellMask	to XkbChangeEnabledControls.  If  you  set  XkbAudibleBellMask
       on,  the	server rings the system	bell when a bell event occurs. This is
       the default. If you set XkbAudibleBellMask off and a bell event occurs,
       the  server  does  not ring the system bell unless you call XkbForceDe-
       viceBell	or XkbForceBell.

       Audible bells are also part of the per-client auto-reset	controls.

       Bell Functions

       Use the functions described in this section to ring bells and to	gener-
       ate bell	events.

       The  input extension has	two types of feedbacks that can	generate bells
       - bell feedback and keyboard feedback. Some of the  functions  in  this
       section	have  bell_class  and bell_id parameters; set them as follows:
       Set bell_class to BellFeedbackClass or KbdFeedbackClass.	A  device  can
       have more than one feedback of each type; set bell_id to	the particular
       bell feedback of	bell_class type.

       Table 2 shows the conditions that cause a bell to sound or an  XkbBell-
       NotifyEvent to be generated when	a bell function	is called.

		    Table 2 Bell Sounding and Bell Event Generating
       Function	called	    AudibleBell	  Server sounds	a bell	 Server	sends an
       XkbDeviceBell	    On		  Yes			 Yes
       XkbDeviceBell	    Off		  No			 Yes
       XkbBell		    On		  Yes			 Yes
       XkbBell		    Off		  No			 Yes
       XkbDeviceBellEvent   On or Off	  No			 Yes
       XkbBellEvent	    On or Off	  No			 Yes
       XkbDeviceForceBell   On or Off	  Yes			 No
       XkbForceBell	    On or Off	  Yes			 No

       If  a compatible	keyboard extension isn't present in the	X server, Xkb-
       ForceBell calls XBell with the specified	display	and  percent  and  re-
       turns  False. Otherwise,	XkbForceBell calls XkbForceDeviceBell with the
       specified display and percent, device_spec =XkbUseCoreKbd, bell_class =
       XkbDfltXIClass,	bell_id	= XkbDfltXIId, window =	None, and name = NULL,
       and returns what	XkbForceDeviceBell returns.

       XkbForceBell does not cause an XkbBellNotify event.

       You can call XkbBell without first initializing the keyboard extension.

       False	      The XkbForceBell function	returns	False when a  compati-
		      ble keyboard extension isn't present in the X server.

       Xkb  generates  XkbBellNotify events for	all bells except for those re-
       sulting from calls to XkbForceDeviceBell	and XkbForceBell.  To  receive
       XkbBellNotify events under all possible conditions, pass	XkbBellNotify-
       Mask in both the	bits_to_change and values_for_bits parameters to XkbS-

       The  XkbBellNotify event	has no event details. It is either selected or
       it is not.  However, you	can call XkbSelectEventDetails using  XkbBell-
       Notify	as  the	 event_type  and  specifying  XkbAllBellEventsMask  in
       bits_to_change and values_for_bits.  This has the same effect as	a call
       to XkbSelectEvents.

       The structure for the XkbBellNotify event type contains:

	  typedef struct _XkbBellNotify	{
	      int	     type;	  /* Xkb extension base	event code */
	      unsigned long  serial;	  /* X server serial number for	event */
	      Bool	     send_event;  /* True => synthetically generated */
	      Display *	     display;	  /* server connection where event generated */
	      Time	     time;	  /* server time when event generated */
	      int	     xkb_type;	  /* XkbBellNotify */
	      unsigned int   device;	  /* Xkb device	ID, will not be	XkbUseCoreKbd */
	      int	     percent;	  /* requested volume as % of max */
	      int	     pitch;	  /* requested pitch in	Hz */
	      int	     duration;	  /* requested duration	in microseconds	*/
	      unsigned int   bell_class;  /* X input extension feedback	class */
	      unsigned int   bell_id;	  /* X input extension feedback	ID */
	      Atom	     name;	  /* "name" of requested bell */
	      Window	     window;	  /* window associated with event */
	      Bool	     event_only;  /* False -> the server did not produce a beep	*/
	  } XkbBellNotifyEvent;

       If  your	 application  needs  to	 generate  visual bell feedback	on the
       screen when it receives a bell event, use the window ID in the XkbBell-
       NotifyEvent, if present.

       XBell(3),   XkbBell(3),	 XkbChangeEnabledControls(3),  XkbForceDevice-
       Bell(3),	XkbSelectEventDetails(3), XkbSelectEvents(3)

X Version 11			 libX11	1.6.12		       XkbForceBell(3)


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