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X11R7.4 - man page for xkbbellevent (x11r4 section 3)

XkbBellEvent(3) 			  XKB FUNCTIONS 			  XkbBellEvent(3)

NAME
       XkbBellEvent  -	Provides  a function that initiates a bell event for the keyboard without
       ringing the bell

SYNOPSIS
       Bool XkbBellEvent ( display, window, percent, name )
	     Display * display ;
	     Window  window ;
	     int  percent ;
	     Atom  name ;

ARGUMENTS
       - display
	      connection to the X server

       - window
	      the event window, or None

       - percent,
	      relative volume, which can range from -100 to 100 inclusive

       - name a bell name, or NULL

DESCRIPTION
       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
	    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 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  Table 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 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
	    events.

	    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
	    XkbBellNotifyEvent
	    ---------------------------------------------------------------------------
	    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, XkbBellEvent imme-
	    diately returns False. Otherwise,  XkbBellEvent  calls  XkbDeviceBellEvent	with  the
	    specified  display,  window,  percent,  and  name,	a device_spec of XkbUseCoreKbd, a
	    bell_class of XkbDfltXIClass, and a bell_id of XkbDfltXIId, and returns  what  XkbDe-
	    viceBellEvent returns.

	    XkbBellEvent generates a XkbBellNotify event.

	    You can call XkbBellEvent without first initializing the keyboard extension.

RETURN VALUES
       False	      The XkbBellEvent immediately returns False, if a compatible keyboard exten-
		      sion isn't present in the X server.

STRUCTURES
       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  parame-
       ters to XkbSelectEvents.

       The  XkbBellNotify  event  has no event details. It is either selected or it is not.  How-
       ever, you can call XkbSelectEventDetails using XkbBellNotify as the event_type and  speci-
       fying  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.

SEE ALSO
       XkbChangeEnabledControls(3),   XkbDeviceBellEvent(3),   XkbForceBell(3),   XkbForceDevice-
       Bell(3), XkbSelectEventDetails(3), XkbSelectEvents(3)

X Version 11				   libX11 1.2.1 			  XkbBellEvent(3)


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