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NAME

       XkbBell - Rings the bell on the default keyboard

SYNOPSIS

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

ARGUMENTS

       - display
              connection to the X server

       - window
              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:

       ·    The default bell

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

       ·    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
       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  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
       T{ SlowKeys and BounceKeys about to be turned on or off
       T}                                                        AX_SlowKeysWarning
       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  XkbAudibleBellMask  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 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
       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,
       XkbBell calls XBell with the specified display and percent, and returns
       False.  Otherwise,  XkbBell  calls  XkbDeviceBell  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
       True.

       If you have disabled the audible bell, the server  does  not  ring  the
       system bell, although it does generate a XkbBellNotify event.

       You can call XkbBell without first initializing the keyboard extension.

RETURN VALUES

       FALSE          The  XkbBell  function returns FALSE if XlibDisplayNoXkb
                      is set.

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
       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.

SEE ALSO

       XBell(3),        XkbBellNotify(3),         XkbChangeEnabledControls(3),
       XkbDeviceBell(3),        XkbForceBell(3),        XkbForceDeviceBell(3),
       XkbUseCoreKbd(3)



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