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CentOS 7.0 - man page for xkbdevicebellevent (centos section 3)

XkbDeviceBellEvent(3)			  XKB FUNCTIONS 		    XkbDeviceBellEvent(3)

       XkbDeviceBellEvent  - Creates a bell event for an X input extension device or for the key-
       board, without ringing the corresponding bell

       Bool XkbDeviceBellEvent	(Display  *display,  Window  window,  unsigned	int  device_spec,
	      unsigned int bell_class, unsigned int bell_id, int percent, Atom name);

       - display
	      connection to the X server

       - window
	      event window, or None

       - device_spec
	      device ID, or XkbUseCoreKbd

       - bell_class
	      input extension bell class for the event

       - bell_id
	      input extension bell ID for the event

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

       - name a bell name, or NULL

       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, disable 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 following:

       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 gener-
	    ate 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

	    Just  as  some  keyboards  can produce keyclicks to indicate when a key is pressed or
	    repeating, Xkb can provide feedback for the controls by using special beep codes. The
	    AccessXFeedback  control  is  used to configure 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 XkbBellNotify 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 receipt 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 Table 1 below; 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  XkbBellNotify 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  XkbAudibleBellMask  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 XkbAudibleBell-
	    Mask off and a bell event occurs, the server does not ring the system bell unless you
	    call XkbForceDeviceBell 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  generate  bell

	    The  input	extension has two types of feedbacks that can generate bells - bell feed-
	    back 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 Kbd-
	    FeedbackClass. 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 XkbBellNotifyEvent 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,  XkbDeviceBellEvent
	    immediately  returns  False.  Otherwise,  XkbDeviceBellEvent  causes an XkbBellNotify
	    event to be sent to all interested clients and returns True. Set percent  to  be  the
	    volume relative to the base volume for the keyboard as described for XBell.

	    In addition, XkbDeviceBellEvent may generate Atom protocol errors as well as XkbBell-
	    Notify events. You can call XkbBell without first initializing  the  keyboard  exten-

       True	      The  XkbDeviceBellEvent  sends  an XkbBellNotify event to to all interested
		      clients and returns True.

       False	      If a compatible keyboard extension isn't present in the  X  server,  XkbDe-
		      viceBellEvent immediately returns False

       Xkb generates XkbBellNotify events for all bells except for those resulting from
	      calls  to  XkbForceDeviceBell  and  XkbForceBell.   To receive XkbBellNotify events
	      under all possible conditions, pass XkbBellNotifyMask in	both  the  bits_to_change
	      and values_for_bits parameters to XkbSelectEvents.

	      The  XkbBellNotify  event has no event details. It is either selected or it is not.
	      However, you can call XkbSelectEventDetails using XkbBellNotify as  the  event_type
	      and  specifying  XkbAllBellNotifyMask  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 XkbBellNotifyEvent, if present.

       XBell(3),   XkbBellNotify(3),   XkbChangeEnabledControls(3),  XkbDeviceBell(3),	XkbForce-
       Bell(3),  XkbForceDeviceBell(3),  XkbSelectEvents(3),  XkbSelectEventDetails(3),  XkbUseC-

X Version 11				   libX11 1.6.0 		    XkbDeviceBellEvent(3)

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