Index of Section 3 Manual Pages
| Interix / SUA | XkbBellEvent.3 | Interix / SUA |
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 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 XkbBell-
Notify 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 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 config-
ure 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 chap-
ter. 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 prede-
fined 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 XkbForce-
Bell.
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 feed-
back. Some of the functions in this section have
bell_class and bell_id parameters; set them as fol-
lows: Set bell_class to BellFeedbackClass or KbdFeed-
backClass. 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, XkbBellEvent immediately returns False.
Otherwise, XkbBellEvent calls XkbDeviceBellEvent with
the specified display, window, percent, and name, a
device_spec of XkbUseCoreKbd, a bell_class of XkbD-
fltXIClass, 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 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 XkbSe-
lectEvents.
The XkbBellNotify event has no event details. It is either
selected or it is not. However, you can call XkbSe-
lectEventDetails using XkbBellNotify as the event_type and
specifying XkbAllBellNotifyMask in bits_to_change and val-
ues_for_bits. This has the same effect as a call to XkbS-
electEvents.
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 win-
dow ID in the XkbBellNotifyEvent, if present.
SEE ALSO
XkbChangeEnabledControls(3), XkbDeviceBellEvent(3), Xkb-
ForceBell(3), XkbForceDeviceBell(3), XkbSelectEventDe-
tails(3), XkbSelectEvents(3)
X Version 11 libX11 1.1.5 XkbBellEvent(3)