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diff --git a/specs/ch04.xml b/specs/ch04.xml deleted file mode 100644 index d35e2b4..0000000 --- a/specs/ch04.xml +++ /dev/null @@ -1,865 +0,0 @@ -<chapter id='Global_Keyboard_Controls'> -<title>Global Keyboard Controls</title> - -<para> -The X Keyboard Extension supports a number of <emphasis> -global key controls</emphasis> -, which affect the way that XKB handles the keyboard as a whole. Many of these -controls make the keyboard more accessible to the physically impaired and are -based on the AccessDOS package<footnote><para> -AccessDOS provides access to the DOS operating system for people with physical -impairments and was developed by the Trace R&D Center at the University of -Wisconsin. For more information on AccessDOS, contact the Trace R&D Center, -Waisman Center and Department of Industrial Engineering, University of -Wisconsin-Madison WI 53705-2280. Phone: 608-262-6966. e-mail: -info@trace.wisc.edu.</para></footnote>. -</para> - -<sect1 id='The_RepeatKeys_Control'> -<title>The RepeatKeys Control</title> - -<para> -The core protocol only allows control over whether or not the entire keyboard -or individual keys should autorepeat when held down. The <emphasis> -RepeatKeys</emphasis> - control extends this capability by adding control over the delay until a key -begins to repeat and the rate at which it repeats. <emphasis> -RepeatKeys</emphasis> - is also coupled with the core autorepeat control; changes to one are always -reflected in the other. -</para> - - -<para> -The <emphasis> -RepeatKeys</emphasis> - control has two parameters. The <emphasis> -autorepeat delay</emphasis> - specifies the delay between the initial press of an autorepeating key and the -first generated repeat event in milliseconds. The <emphasis> -autorepeat interval</emphasis> - specifies the delay between all subsequent generated repeat events in -milliseconds. -</para> - - -<sect2 id='The_PerKeyRepeat_Control'> -<title>The PerKeyRepeat Control</title> - -<para> -When <emphasis> -RepeatKeys</emphasis> - are active, the <emphasis> -PerKeyRepeat</emphasis> - control specifies whether or not individual keys should autorepeat when held -down. XKB provides the <emphasis> -PerKeyRepeat</emphasis> - for convenience only, and it always parallels the <emphasis> -auto-repeats</emphasis> - field of the core protocol <emphasis> -GetKeyboardControl</emphasis> - request — changes to one are always reflected in the other. -</para> - - -</sect2> -<sect2 id='Detectable_Autorepeat'> -<title>Detectable Autorepeat</title> - -<para> -The X server usually generates both press and release events whenever an -autorepeating key is held down. If an XKB-aware client enables the <emphasis> -DetectableAutorepeat</emphasis> - per-client option for a keyboard, the server sends that client a key release -event only when the key is <emphasis> -physically</emphasis> - released. For example, holding down a key to generate three characters without -detectable autorepeat yields: -</para> - -<literallayout class='monospaced'> -Press <emphasis>-></emphasis> Release <emphasis>-></emphasis> Press <emphasis>-></emphasis> Release <emphasis>-></emphasis> Press <emphasis>-></emphasis> Release -</literallayout> - -<para> -If detectable autorepeat is enabled, the client instead receives: -</para> - -<literallayout class='monospaced'> -Press<emphasis>-></emphasis> Press <emphasis>-></emphasis> Press <emphasis>-></emphasis> Release -</literallayout> - -<para> -Note that only clients that request detectable autorepeat are affected; other -clients continue to receive both press and release events for autorepeating -keys. Also note that support for detectable autorepeat is optional; servers are -not required to support detectable autorepeat, but they must correctly report -whether or not it is supported. -</para> - - -<para> -<link linkend='Querying_and_Changing_Per_Client_Flags'>Querying and Changing Per-Client -Flags</link> describes the <emphasis> -XkbPerClientFlags</emphasis> - request, which reports or changes values for all of the per-client flags, and -which lists the per-client flags that are supported. -</para> - - -</sect2> -</sect1> -<sect1 id='The_SlowKeys_Control'> -<title>The SlowKeys Control</title> - -<para> -Some users often bump keys accidentally while moving their hand or typing stick -toward the key they want. Usually, the keys that are bumped accidentally are -hit only for a very short period of time. The <emphasis> -SlowKeys</emphasis> - control helps filter these accidental bumps by telling the server to wait a -specified period, called the <emphasis> -SlowKeys acceptance delay</emphasis> -, before delivering key events. If the key is released before this period -elapses, no key events are generated. The user can then bump any number of keys -on their way to the one they want without generating unwanted characters. Once -they have reached the key they want, they can then hold it long enough for -<emphasis> -SlowKeys</emphasis> - to accept it. -</para> - - -<para> -The <emphasis> -SlowKeys</emphasis> - control has one parameter; the <emphasis> -slow keys delay</emphasis> - specifies the length of time, in milliseconds, that a key must be held down -before it is accepted. -</para> - - -<para> -When <emphasis> -SlowKeys</emphasis> - are active, the X Keyboard Extension reports the initial press, acceptance, -rejection or release of any key to interested clients using <emphasis> -AccessXNotify</emphasis> - events. The <emphasis> -AccessXNotify</emphasis> - event is described in more detail in <link linkend='Events'>Events</link>. -</para> - -</sect1> -<sect1 id='The_BounceKeys_Control'> -<title>The BounceKeys Control</title> - -<para> -Some people with physical impairments accidentally "bounce" on a key when they -press it. That is, they press it once, then accidentally press it again -immediately. The <emphasis> -BounceKeys</emphasis> - control temporarily disables a key after it has been pressed, effectively -"debouncing" the keyboard. -</para> - - -<para> -The <emphasis> -BounceKeys</emphasis> - has a single parameter. The <emphasis> -BounceKeys delay</emphasis> - specifies the period of time, in milliseconds, that the key is disabled after -it is pressed. -</para> - - -<para> -When <emphasis> -BounceKeys</emphasis> - are active, the server reports the acceptance or rejection of any key to -interested clients by sending an <emphasis> -AccessXNotify</emphasis> - event. The <emphasis> -AccessXNotify</emphasis> - event is described in more detail in <link linkend='Events'>Events</link>. -</para> - -</sect1> -<sect1 id='The_StickyKeys_Control'> -<title>The StickyKeys Control</title> - -<para> -Some people find it difficult or impossible to press two keys at once. The -<emphasis> -StickyKeys</emphasis> - control makes it easier for them to type by changing the behavior of the -modifier keys. When <emphasis> -StickyKeys</emphasis> - are enabled, a modifier is latched when the user presses it just once, so the -user can first press a modifier, release it, then press another key. For -example, to get an exclamation point (!) on a PC-style keyboard, the user can -press the <emphasis> -Shift</emphasis> - key, release it, then press the <emphasis> -1</emphasis> - key. -</para> - - -<para> -By default, <emphasis> -StickyKeys</emphasis> - also allows users to lock modifier keys without requiring special locking -keys. The user can press a modifier twice in a row to lock it, and then unlock -it by pressing it one more time. -</para> - - -<para> -Modifiers are automatically unlatched when the user presses a non-modifier key. -For instance, to enter the sequence <emphasis> -Shift</emphasis> -+<emphasis> -Ctrl</emphasis> -+<emphasis> -Z</emphasis> - the user could press and release the <emphasis> -Shift</emphasis> - key to latch the <emphasis> -Shift</emphasis> - modifier, then press and release the <emphasis> -Ctrl</emphasis> - key to latch the <emphasis> -Control</emphasis> - modifier — the <emphasis> -Ctrl</emphasis> - key is a modifier key, so pressing it does not unlatch the <emphasis> -Shift</emphasis> - modifier, but leaves both the <emphasis> -Shift</emphasis> - and <emphasis> -Control</emphasis> - modifiers latched, instead. When the user presses the <emphasis> -Z</emphasis> - key, it will be as though the user pressed <emphasis> -Shift</emphasis> -+<emphasis> -Ctrl</emphasis> -+<emphasis> -Z</emphasis> - simultaneously. The <emphasis> -Z</emphasis> - key is not a modifier key, so the <emphasis> -Shift</emphasis> - and <emphasis> -Control</emphasis> - modifiers are unlatched after the event is generated. -</para> - - -<para> -A locked a modifier remains in effect until the user unlocks it. For example, -to enter the sequence ("XKB") on a PC-style keyboard with a typical US/ASCII -layout, the user could press and release the <emphasis> -Shift</emphasis> - key twice to lock the <emphasis> -Shift</emphasis> - modifier. Then, when the user presses the <emphasis> -9</emphasis> -, <emphasis> -‘</emphasis> -, <emphasis> -x</emphasis> -, <emphasis> -k</emphasis> -, <emphasis> -b</emphasis> -, <emphasis> -‘</emphasis> -, and <emphasis> -0</emphasis> - keys in sequence, it will generate ("XKB"). To unlock the <emphasis> -Shift</emphasis> - modifier, the user can press and release the <emphasis> -Shift</emphasis> - key. -</para> - - -<para> -Two option flags modify the behavior of the <emphasis> -StickyKeys</emphasis> - control: -</para> - -<itemizedlist> -<listitem> - <para>If the <emphasis> -XkbAX_TwoKeys</emphasis> - flag is set, XKB automatically turns <emphasis> -StickyKeys</emphasis> - off if the user presses two or more keys at once. This serves to automatically -disable StickyKeys when a user who does not require sticky keys is using the -keyboard. - </para> -</listitem> -<listitem> - <para>The <emphasis> -XkbAX_LatchToLock</emphasis> - controls the locking behavior of <emphasis> -StickyKeys</emphasis> -; the <emphasis> -StickyKeys</emphasis> - control only locks modifiers as described above if the <emphasis> -XkbAX_LatchToLock</emphasis> - flag is set. - </para> -</listitem> -</itemizedlist> - -</sect1> -<sect1 id='The_MouseKeys_Control'> -<title>The MouseKeys Control</title> - -<para> -The <emphasis> -MouseKeys</emphasis> - control lets a user control all the mouse functions from the keyboard. When -<emphasis> -MouseKeys</emphasis> - are enabled, all keys with <emphasis> -MouseKeys</emphasis> - actions bound to them generate core pointer events instead of normal key press -and release events. -</para> - - -<para> -The <emphasis> -MouseKeys</emphasis> - control has a single parameter, the <emphasis> -mouse keys default button</emphasis> -, which specifies the core pointer button to be used by mouse keys actions that -do not explicitly specify a button. -</para> - - -</sect1> -<sect1 id='The_MouseKeysAccel_Control'> -<title>The MouseKeysAccel Control</title> - -<para> -If the <emphasis> -MouseKeysAccel</emphasis> - control is enabled, the effect of a pointer motion action changes as a key is -held down. The <emphasis> -mouse keys delay</emphasis> - specifies the amount of time between the initial key press and the first -repeated motion event. The <emphasis> -mouse keys interval</emphasis> - specifies the amount of time between repeated mouse keys events. The <emphasis> -steps to maximum acceleration</emphasis> - field specifies the total number of events before the key is travelling at -maximum speed. The <emphasis> -maximum acceleration</emphasis> - field specifies the maximum acceleration. The <emphasis> -curve</emphasis> - parameter controls the ramp used to reach maximum acceleration. -</para> - - -<para> -When <emphasis> -MouseKeys</emphasis> - are active and a <emphasis> -SA_MovePtr</emphasis> - key action (see <link linkend='Key_Actions'>Key -Actions</link>) is activated, a pointer motion event is generated immediately. -If <emphasis> -MouseKeysAccel</emphasis> - is enabled and if acceleration is enabled for the key in question, a second -event is generated after <emphasis> -mouse keys delay </emphasis> -milliseconds, and additional events are generated every <emphasis> -mouse keys interval</emphasis> - milliseconds for as long as the key is held down. -</para> - - -<sect2 id='Relative_Pointer_Motion'> -<title>Relative Pointer Motion</title> - -<para> -If the <emphasis> -SA_MovePtr</emphasis> - action specifies relative motion, events are generated as follows: The initial -event always moves the cursor the distance specified in the action; after -<emphasis> -steps to maximum acceleration</emphasis> - events have been generated, all subsequent events move the pointer the -distance specified in the action times the <emphasis> -maximum acceleration.</emphasis> - Events after the first but before maximum acceleration has been achieved are -accelerated according to the formula: -</para> - -<mediaobject> - <imageobject> - <imagedata format="SVG" fileref="XKBproto-1.svg"/> - </imageobject> -</mediaobject> - - -<para> -Where <emphasis> -action_delta</emphasis> - is the offset specified by the mouse keys action, <emphasis> -max_accel </emphasis> -and <emphasis> -steps_to_max</emphasis> - are parameters to the <emphasis> -MouseKeysAccel</emphasis> - ctrl, and the curveFactor is computed using the <emphasis> -MouseKeysAccel</emphasis> - <emphasis> -curve</emphasis> - parameter as follows: -</para> - -<mediaobject> - <imageobject> <imagedata format="SVG" fileref="XKBproto-2.svg"/> - </imageobject> - </mediaobject> - - -<para> -With the result that a <emphasis> -curve</emphasis> - of <emphasis> -0</emphasis> - causes the distance moved to increase linearly from <emphasis> -action_delta</emphasis> - to <mediaobject> - <imageobject> <imagedata format="SVG" fileref="XKBproto-3.svg"/> - </imageobject> - </mediaobject> - -, and the minimum legal <emphasis> -curve</emphasis> - of -<emphasis> -1000</emphasis> - causes all events after the first move at <emphasis> -max_accel</emphasis> -. A negative <emphasis> -curve</emphasis> - causes an initial sharp increase in acceleration which tapers off, while a -positive curve yields a slower initial increase in acceleration followed by a -sharp increase as the number of pointer events generated by the action -approaches <emphasis> -steps_to_max</emphasis> -. -</para> - - -</sect2> -<sect2 id='Absolute_Pointer_Motion'> -<title>Absolute Pointer Motion</title> - -<para> -If an <emphasis> -SA_MovePtr</emphasis> - action specifies an absolute position for one of the coordinates but still -allows acceleration, all repeated events contain any absolute coordinates -specified in the action. -</para> - - -</sect2> -</sect1> -<sect1 id='The_AccessXKeys_Control'> -<title>The AccessXKeys Control</title> - -<para> -If <emphasis> -AccessXKeys</emphasis> - is enabled many controls can also be turned on or off from the keyboard by -entering the following standard key sequences: -</para> - -<itemizedlist> -<listitem> - <para>Holding down a shift key by itself for eight seconds toggles the -<emphasis> -SlowKeys</emphasis> - control. - </para> -</listitem> -<listitem> - <para>Pressing and releasing a shift key five times in a row without any -intervening key events and with less than 30 seconds delay between consecutive -presses toggles the state of the <emphasis> -StickyKeys</emphasis> - control. - </para> -</listitem> -<listitem> - <para>Simultaneously operating two or more modifier keys deactivates the -<emphasis> -StickyKeys</emphasis> - control. - </para> -</listitem> -</itemizedlist> - -<para> -Some of these key sequences optionally generate audible feedback of the change -in state, as described in <link linkend='The_AccessXFeedback_Control'>The -AccessXFeedback Control</link>, or cause <emphasis> -XkbAccessXNotify</emphasis> - events as described in <link linkend='Events'>Events</link>. -</para> - - -</sect1> -<sect1 id='The_AccessXTimeout_Control'> -<title>The AccessXTimeout Control</title> - -<para> -In environments where computers are shared, features such as <emphasis> -SlowKeys</emphasis> - present a problem: if <emphasis> -SlowKeys</emphasis> - is on, the keyboard can appear to be unresponsive because keys have no effect -unless they are held for a certain period of time. To help address this -problem, XKB provides an <emphasis> -AccessXTimeout</emphasis> - control to automatically change the value of any global controls or AccessX -options if the keyboard is idle for a specified period of time. -</para> - - -<para> -The AccessXTimeout control has a number of parameters which affect the duration -of the timeout and the features changed when the timeout expires. -</para> - - -<para> -The <emphasis> -AccessX Timeout</emphasis> - field specifies the number of seconds the keyboard must be idle before the -global controls and AccessX options are modified. The <emphasis> -AccessX Options Mask</emphasis> - field specifies which values in the <emphasis> -AccessX Options</emphasis> - field are to be changed, and the <emphasis> -AccessX Options Values</emphasis> - field specifies the new values for those options. The <emphasis> -AccessX Controls Mask</emphasis> - field specifies which controls are to be changed in the global set of -<emphasis> -enabled controls</emphasis> -, and the <emphasis> -AccessX Controls Values</emphasis> - field specifies the new values for those controls. -</para> - - -</sect1> -<sect1 id='The_AccessXFeedback_Control'> -<title>The AccessXFeedback Control</title> - -<para> -If <emphasis> -AccessXFeedback</emphasis> - is enabled, special beep-codes indicate changes in keyboard controls (or some -key events when <emphasis> -SlowKeys</emphasis> - or <emphasis> -StickyKeys</emphasis> - are active). Many beep codes sound as multiple tones, but XKB reports a single -<emphasis> -XkbBellNotify</emphasis> - event for the entire sequence of tones. -</para> - - -<para> -All feedback tones are governed by the <emphasis> -AudibleBell</emphasis> - control. Individual feedback tones can be explicitly enabled or disabled using -the <emphasis> -accessX options mask</emphasis> - or set to deactivate after an idle period using the <emphasis> -accessX timeout options mask</emphasis> -. XKB defines the following feedback tones: -</para> - -<informaltable frame='topbot'> -<?dbfo keep-together="always" ?> -<tgroup cols='4' align='left' colsep='0' rowsep='0'> -<colspec colname='c1' colwidth='1.0*'/> -<colspec colname='c2' colwidth='1.5*'/> -<colspec colname='c3' colwidth='1.5*'/> -<colspec colname='c4' colwidth='1.5*'/> -<thead> - <row rowsep='1'> - <entry>Feedback Name</entry> - <entry>Bell Name</entry> - <entry>Default Sound</entry> - <entry>Indicates</entry> - </row> -</thead> -<tbody> - <row> - <entry>FeatureFB</entry> - <entry>AX_FeatureOn</entry> - <entry>rising tone</entry> - <entry>Keyboard control enabled</entry> - </row> - <row> - <entry> </entry> - <entry>AX_FeatureOff</entry> - <entry>falling tone</entry> - <entry>Keyboard control disabled</entry> - </row> - <row> - <entry> </entry> - <entry>AX_FeatureChange</entry> - <entry>two tones</entry> - <entry>Several controls changed state</entry> - </row> - <row> - <entry>IndicatorFB</entry> - <entry>AX_IndicatorOn</entry> - <entry>high tone</entry> - <entry>Indicator Lit</entry> - </row> - <row> - <entry> </entry> - <entry>AX_IndicatorOff</entry> - <entry>low tone</entry> - <entry>Indicator Extinguished</entry> - </row> - <row> - <entry> </entry> - <entry>AX_IndicatorChange</entry> - <entry>two high tones</entry> - <entry>Several indicators changed state</entry> - </row> - <row> - <entry>SlowWarnFB</entry> - <entry>AX_SlowKeysWarning</entry> - <entry>three high tones</entry> - <entry>Shift key held for four seconds</entry> - </row> - <row> - <entry>SKPressFB</entry> - <entry>AX_SlowKeyPress</entry> - <entry>single tone</entry> - <entry>Key press while <emphasis> -SlowKeys</emphasis> - are on</entry> - </row> - <row> - <entry>SKReleaseFB</entry> - <entry>AX_SlowKeyRelease</entry> - <entry>single tone</entry> - <entry>Key release while <emphasis> -SlowKeys</emphasis> - are on</entry> - </row> - <row> - <entry>SKAcceptFB</entry> - <entry>AX_SlowKeyAccept</entry> - <entry>single tone</entry> - <entry>Key event accepted by <emphasis> -SlowKeys</emphasis> -</entry> - </row> - <row> - <entry>SKRejectFB</entry> - <entry>AX_SlowKeyReject</entry> - <entry>low tone</entry> - <entry>Key event rejected by <emphasis> -SlowKeys</emphasis> -</entry> - </row> - <row> - <entry>StickyKeysFB</entry> - <entry>AX_StickyLatch</entry> - <entry>low tone then high tone</entry> - <entry>Modifier latched by <emphasis> -StickyKeys</emphasis> -</entry> - </row> - <row> - <entry> </entry> - <entry>AX_StickyLock</entry> - <entry>high tone</entry> - <entry>Modifier locked by <emphasis> -StickyKeys</emphasis> -</entry> - </row> - <row> - <entry> </entry> - <entry>AX_StickyUnlock</entry> - <entry>low tone</entry> - <entry>Modifier unlocked by <emphasis> -StickyKeys</emphasis> -</entry> - </row> - <row> - <entry>BKRejectFB</entry> - <entry>AX_BounceKeysReject</entry> - <entry>low tone</entry> - <entry>Key event rejected by <emphasis> -BounceKeys</emphasis> -</entry> - </row> -</tbody> -</tgroup> -</informaltable> - -<para> -Implementations that cannot generate continuous tones may generate multiple -beeps instead of falling and rising tones; for example, they can generate a -high-pitched beep followed by a low-pitched beep instead of a continuous -falling tone. -</para> - - -<para> -If the physical keyboard bell is not very capable, attempts to simulate a -continuous tone with multiple bells can sound horrible. Set the <emphasis> -DumbBellFB</emphasis> - AccessX option to inform the server that the keyboard bell is not very capable -and that XKB should use only simple bell combinations. Keyboard capabilities -vary wildly, so the sounds generated for the individual bells when the -<emphasis> -DumbBellFB</emphasis> - option is set are implementation specific. -</para> - - -</sect1> -<sect1 id='The_Overlay1_and_Overlay2_Controls'> -<title>The Overlay1 and Overlay2 Controls</title> - -<para> -A keyboard overlay allows some subset of the keyboard to report alternate -keycodes when the overlay is enabled. For example a keyboard overlay can be -used to simulate a numeric or editing keypad on keyboard that does not actually -have one by generating alternate of keycodes for some keys when the overlay is -enabled. This technique is very common on portable computers and embedded -systems with small keyboards. -</para> - - -<para> -XKB includes direct support for two keyboard overlays, using the <emphasis> -Overlay1</emphasis> - and <emphasis> -Overlay2</emphasis> - controls. When <emphasis> -Overlay1</emphasis> - is enabled, all of the keys that are members of the first keyboard overlay -generate an alternate keycode. When <emphasis> -Overlay2</emphasis> - is enabled, all of the keys that are members of the second keyboard overlay -generate an alternate keycode. -</para> - - -<para> -To specify the overlay to which a key belongs and the alternate keycode it -should generate when that overlay is enabled, assign it either the <emphasis> -KB_Overlay1</emphasis> - or <emphasis> -KB_Overlay2</emphasis> - key behaviors, as described in <link linkend='Key_Behavior'> -Key Behavior</link>. -</para> - - -</sect1> -<sect1 id='Boolean_Controls_and_The_EnabledControls_Control'> -<title>"Boolean" Controls and The EnabledControls Control</title> - -<para> -All of the controls described above, along with the <emphasis> -AudibleBell</emphasis> - control (described in <link linkend='Disabling_Server_Generated_Bells'>Disabling -Server Generated Bells</link>) and the <emphasis> -IgnoreGroupLock</emphasis> - control (described in <link linkend='Server_Internal_Modifiers_and_Ignore_Locks_Behavior'>Server -Internal Modifiers and Ignore Locks Behavior</link>) comprise the <emphasis> -boolean controls</emphasis> -. In addition to any parameters listed in the descriptions of the individual -controls, the boolean controls can be individually enabled or disabled by -changing the value of the <emphasis> -EnabledControls</emphasis> - control. -</para> - - -<para> -The following <emphasis> -non-boolean</emphasis> - controls are always active and cannot be changed using the <emphasis> -EnabledControls</emphasis> - control or specified in any context that accepts only boolean controls: -<emphasis> -GroupsWrap</emphasis> - (<link linkend='Computing_Effective_Modifier_and_Group'>Computing Effective Modifier and -Group</link>), <emphasis> -EnabledControls</emphasis> -, <emphasis> -InternalMods</emphasis> - (<link linkend='Server_Internal_Modifiers_and_Ignore_Locks_Behavior'>Server Internal Modifiers and -Ignore Locks Behavior</link>), and <emphasis> -IgnoreLockMods</emphasis> - (<link linkend='Server_Internal_Modifiers_and_Ignore_Locks_Behavior'>Server Internal Modifiers and -Ignore Locks Behavior</link>) and <emphasis> -PerKeyRepeat</emphasis> - (<link linkend='The_RepeatKeys_Control'>The RepeatKeys Control</link>) -</para> - - -</sect1> -<sect1 id='Automatic_Reset_of_Boolean_Controls'> -<title>Automatic Reset of Boolean Controls</title> - -<para> -The <emphasis> -auto-reset controls</emphasis> - are a per-client value which consist of two masks that can contain any of the -boolean controls (see <link linkend='Boolean_Controls_and_The_EnabledControls_Control'>"Boolean" -Controls and The EnabledControls Control</link>). Whenever the client exits -for any reason, any boolean controls specified in the <emphasis> -auto-reset mask</emphasis> - are set to the corresponding value from the <emphasis> -auto-reset values</emphasis> - mask. This makes it possible for clients to "clean up after themselves" -automatically, even if abnormally terminated. -</para> - - -<para> -For example, a client that replace the keyboard bell with some other audible -cue might want to turn off the <emphasis> -AudibleBell</emphasis> - control (<link linkend='Disabling_Server_Generated_Bells'>Disabling Server -Generated Bells</link>) to prevent the server from also generating a sound and -thus avoid cacophony. If the client were to exit without resetting the -<emphasis> -AudibleBell </emphasis> -control, the user would be left without any feedback at all. Setting <emphasis> -AudibleBell</emphasis> - in both the auto-reset mask and auto-reset values guarantees that the audible -bell will be turned back on when the client exits. -</para> -</sect1> -</chapter> |