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XkbForceDeviceBell(3)             XKB FUNCTIONS            XkbForceDeviceBell(3)




NAME

       XkbForceDeviceBell - Rings the bell on any keyboard, overriding user
       preference settings for audible bells


SYNOPSIS

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


ARGUMENTS

       display
              connection to the X server

       window event window, or None

       device_spec
              device ID, or XkbUseCoreKbd

       bell_class
              input extension class of the bell to be rung

       bell_id
              input extension ID of the bell to be rung

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


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 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                                     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 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,
       XkbForceDeviceBell immediately returns False. Otherwise,
       XkbForceDeviceBell rings the bell as specified for the display and
       keyboard device and returns True. Set percent to be the volume relative
       to the base volume for the keyboard as described for XBell.

       There is no name parameter because XkbForceDeviceBell does not cause an
       XkbBellNotify event.

       You can call XkbBell without first initializing the keyboard extension.


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 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
       XkbBellNotifyEvent, if present.


SEE ALSO

       XBell(3), XkbBell(3), XkbBellNotify(3), XkbChangeEnabledControls(3),
       XkbForceDeviceBell(3),
       XkbSelectEventDetails(3), XkbSelectEvents(3)







X Version 11                      libX11 1.8.2             XkbForceDeviceBell(3)

xorg-libX11 1.8.2 - Generated Sat Nov 19 06:26:48 CST 2022
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