XKB FUNCTIONS XkbForceBell(3x11)
NAME
XkbForceBell - Overrides user preference settings for audi-
ble bells to ring the bell on the default keyboardSYNOPSIS
cc [ flag... ] file... -lX11 [ library... ]
Bool XkbForceBell (Display *display, int percent);
ARGUMENTS- display
connection to the X server- percent
volume for the bell, which can range from -100 to 100
inclusiveDESCRIPTION
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 any of the bell types previously listed.You can disable audible bells on a global basis. For exam-
ple, 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 X Version 11 Last change: libX11 1.3.5 1XKB FUNCTIONS XkbForceBell(3x11)
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 cal-
ling one of the functions that force the ringing of a bellin spite of the setting of the AudibleBell control - XkbFor-
ceDeviceBell 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 NamesYou can associate a name to an act of ringing a bell by con-
verting 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 the 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 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
X Version 11 Last change: libX11 1.3.5 2XKB FUNCTIONS XkbForceBell(3x11)
StickyKeys key unlocked AX_StickyUnlock
Audible BellsUsing Xkb you can generate bell events that do not neces-
sarily 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 whena bell event occurs. This is the default. If you set XkbAu-
dibleBellMask off and a bell event occurs, the server does not ring the system bell unless you call XkbForceDeviceBellor 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 gen-
erate 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 BellFeed-
backClass or KbdFeedbackClass. A device can have more thanone 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 X Version 11 Last change: libX11 1.3.5 3XKB FUNCTIONS XkbForceBell(3x11)
XkbDeviceForceBell On or Off Yes NoXkbForceBell On or Off Yes No
If a compatible keyboard extension isn't present in the Xserver, XkbForceBell calls XBell with the specified display
and percent and returns False. Otherwise, XkbForceBell calls
XkbForceDeviceBell with the specified display and percent,device_spec =XkbUseCoreKbd, bell_class = XkbDfltXIClass,
bell_id = XkbDfltXIId, window = None, and name = NULL, and
returns what XkbForceDeviceBell returns.XkbForceBell does not cause an XkbBellNotify event.
You can call XkbBell without first initializing the keyboard extension. RETURNS VALUESFalse The XkbForceBell function returns False when
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 */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 */
X Version 11 Last change: libX11 1.3.5 4XKB FUNCTIONS XkbForceBell(3x11)
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(3x11), XkbBell(3x11), XkbChangeEnabledControls(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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