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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  dura-tion, duration,
       tion,  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  pur-poses purposes
       poses  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  pre-viously previously
            viously listed.

            You  can  disable  audible bells on a global basis. For example, a client that replaces the key-board keyboard
            board 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; the name is included in any bell event sent  to  clients
            that have requested to receive XkbBellNotify events.


                              Table 1 Predefined Bells
            --------------------------------------------------------------Action -------------------------------------------------------------Action
            Action                                     Named Bell
            --------------------------------------------------------------Indicator -------------------------------------------------------------Indicator
            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 XkbBellNotify
            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 XkbAudibleBellMask to XkbChangeEnabled-Controls. XkbChangeEnabledControls.
            Controls.   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 key-board keyboard
            board 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 --------------------------------------------------------------------------Function
            Function called      AudibleBell   Server sounds a bell   Server sends an
            XkbBellNotifyEvent
            ---------------------------------------------------------------------------XkbDeviceBell --------------------------------------------------------------------------XkbDeviceBell
            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  immediately
            returns False. Otherwise, XkbBellEvent calls XkbDeviceBellEvent with the specified display, win-dow, window,
            dow, percent, and name, a device_spec of XkbUseCoreKbd, a bell_class of  XkbDfltXIClass,  and  a
            bell_id of XkbDfltXIId, and returns what XkbDeviceBellEvent 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 extension isn't
                      present in the X server.

STRUCTURES
       Xkb generates XkbBellNotify events for all bells except for those resulting from calls to XkbForceDe-viceBell XkbForceDeviceBell
       viceBell  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
       XkbChangeEnabledControls(3),  XkbDeviceBellEvent(3),  XkbForceBell(3),  XkbForceDeviceBell(3), XkbSe-lectEventDetails(3), XkbSelectEventDetails(3),
       lectEventDetails(3), XkbSelectEvents(3)






X Version 11                                    libX11 1.2.1                                 XkbBellEvent(3)