XKB FUNCTIONS XkbBellEvent(3x11)
NAME
XkbBellEvent - Provides a function that initiates a bell
event for the keyboard without ringing the bellSYNOPSIS
cc [ flag... ] file... -lX11 [ library... ]
Bool XkbBellEvent (Display *display, Window window, int per-
cent, 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 NULLDESCRIPTION
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 abell_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 notconnected 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 X Version 11 Last change: libX11 1.3.5 1XKB FUNCTIONS XkbBellEvent(3x11)
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 withsome other audible cue might want to turn off the Audi-
bleBell control to prevent the server from also gen-
erating 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 ofa bell in spite of the setting of the AudibleBell con-
trol - XkbForceDeviceBell or XkbForceBell. In this case
the server does not generate a bell event.Just as some keyboards can produce keyclicks to indi-
cate when a key is pressed or repeating, Xkb can pro-
vide feedback for the controls by using special beep codes. The AccessXFeedback control is used to configurethe specific types of operations that generate feed-
back. 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
X Version 11 Last change: libX11 1.3.5 2XKB FUNCTIONS XkbBellEvent(3x11)
More than one control changed state AX_FeatureChange
SlowKeys and BounceKeys about to be AX_SlowKeysWarning
turned on or offSlowKeys 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 dis-
able the audible bell (the system bell) and then listenfor XkbBellNotify events. When it receives a XkbBellNo-
tify 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 cangenerate 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. X Version 11 Last change: libX11 1.3.5 3XKB FUNCTIONS XkbBellEvent(3x11)
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 YesXkbBellEvent 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 theX server, XkbBellEvent immediately returns False. Oth-
erwise, XkbBellEvent calls XkbDeviceBellEvent with the
specified display, window, percent, and name, adevice_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 forthose resulting from calls to XkbForceDeviceBell and XkbFor-
ceBell. To receive XkbBellNotify events under all possible conditions, pass XkbBellNotifyMask in both thebits_to_change and values_for_bits parameters to XkbSelec-
tEvents. The XkbBellNotify event has no event details. It is eitherselected or it is not. However, you can call XkbSelec-
tEventDetails 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 */ X Version 11 Last change: libX11 1.3.5 4XKB FUNCTIONS XkbBellEvent(3x11)
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(3x11), XkbDeviceBellEvent(3x11), XkbForceBell(3x11), XkbForceDeviceBell(3x11), XkbSelectEventDetails(3x11), XkbSelectEvents(3x11)ATTRIBUTES
See attributes(5) for descriptions of the following attri-
butes:____________________________________________________________
| ATTRIBUTE TYPE | ATTRIBUTE VALUE |
|_____________________________|_____________________________|
| Availability | x11/library/libx11 ||_____________________________|_____________________________|
| Interface Stability | Committed ||_____________________________|_____________________________|
| MT-Level | See XInitThreads(3X11) |
|_____________________________|_____________________________|
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