www.LinuxHowtos.org

XkbSetAccessXTimeout

Section: XKB FUNCTIONS (3)
Updated: libX11 1.6.4
Index Return to Main Contents

NAME

XkbSetAccessXTimeout - Configures the AccessXTimeout options for a keyboard device

SYNOPSIS

Bool XkbSetAccessXTimeout (Display *display, unsigned int device_spec, unsigned short timeout, unsigned int ctrls_mask, unsigned int ctrls_values, unsigned short opts_mask, unsigned short opts_values);

ARGUMENTS

- display: connection to X server
- device_spec: device to configure, or XkbUseCoreKbd
- timeout: seconds idle until AccessXTimeout occurs
- ctrls_mask: boolean controls to modify
- ctrls_values: new bits for controls selected by ctrls_mask
- opts_mask: ax_options to change
- opts_values: new bits for ax_options selected by opts_mask

DESCRIPTION

In environments where computers are shared, features such as SlowKeys present a problem: if SlowKeys is on, the keyboard can appear to be unresponsive because keys are not accepted until they are held for a certain period of time. To help solve this problem, Xkb provides an AccessXTimeout control to automatically change the enabled/disabled state of any boolean controls and to change the value of the AccessXKeys and AccessXFeedback control attributes if the keyboard is idle for a specified period of time.

When a timeout as specified by AccessXTimeout occurs and a control is consequently modified, Xkb generates an XkbControlsNotify event. For more information on XkbControlsNotify events.

timeout specifies the number of seconds the keyboard must be idle before the controls are modified. ctrls_mask specifies what controls are to be enabled or disabled, and ctrls_values specifies whether those controls are to be enabled or disabled. The bit values correspond to those for enabling and disabling boolean controls using XkbChangeEnabledControls.
The opts_mask field specifies which attributes of the AccessXKeys and AccessXFeedback controls are to be changed, and opts_values specifies the new values for those options. The bit values correspond to those for the ax_options field of an XkbDescRec.

XkbSetAccessXTimeout sends a request to configure the AccessXTimeout control to the server. It does not wait for a reply, and normally returns True. If a compatible version of the Xkb extension is not available in the server, XkbSetAccessXTimeout returns False.

RETURN VALUES

True: The XkbSetAccessXTimeout function returns True when a compatible version of the Xkb extension is available in the server.
False: The XkbSetAccessXTimeout function returns False when a compatible version of the Xkb extension is not available in the server.

STRUCTURES

The complete description of an Xkb keyboard is given by an XkbDescRec. The component structures in the XkbDescRec represent the major Xkb components.

typedef struct {
   struct _XDisplay * display;      /* connection to X server */
   unsigned short     flags;        /* private to Xkb, do not modify */
   unsigned short     device_spec;  /* device of interest */
   KeyCode            min_key_code; /* minimum keycode for device */
   KeyCode            max_key_code; /* maximum keycode for device */
   XkbControlsPtr     ctrls;        /* controls */
   XkbServerMapPtr    server;       /* server keymap */
   XkbClientMapPtr    map;          /* client keymap */
   XkbIndicatorPtr    indicators;   /* indicator map */
   XkbNamesPtr        names;        /* names for all components */
   XkbCompatMapPtr    compat;       /* compatibility map */
   XkbGeometryPtr     geom;         /* physical geometry of keyboard */
} XkbDescRec, *XkbDescPtr;

The display field points to an X display structure. The flags field is private to the library: modifying flags may yield unpredictable results. The device_spec field specifies the device identifier of the keyboard input device, or XkbUseCoreKeyboard, which specifies the core keyboard device. The min_key_code and max_key_code fields specify the least and greatest keycode that can be returned by the keyboard.

Each structure component has a corresponding mask bit that is used in function calls to indicate that the structure should be manipulated in some manner, such as allocating it or freeing it. These masks and their relationships to the fields in the XkbDescRec are shown in Table 1.

Table 1 Mask Bits for XkbDescRec

Mask Bit	XkbDescRec Field	Value

XkbControlsMask	ctrls	(1L<<0)
XkbServerMapMask	server	(1L<<1)
XkbIClientMapMask	map	(1L<<2)
XkbIndicatorMapMask	indicators	(1L<<3)
XkbNamesMask	names	(1L<<4)
XkbCompatMapMask	compat	(1L<<5)
XkbGeometryMask	geom	(1L<<6)
XkbAllComponentsMask	All Fields	(0x7f)

The structure for the XkbControlsNotify event is defined as follows:


    typedef struct {
        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;      /* XkbCompatMapNotify */
        int           device;        /* Xkb device ID, will not be XkbUseCoreKbd */
        unsigned int  changed_ctrls; /* bits indicating which controls data have changed*/
        unsigned int  enabled_ctrls; /* controls currently enabled in server */
        unsigned int  enabled_ctrl_changes; /* bits indicating enabled/disabled controls */
        int           num_groups;    /* current number of keyboard groups */
        KeyCode       keycode;       /* != 0 => keycode of key causing change */
        char          event_type;    /* Type of event causing change */
        char          req_major;     /* major event code of event causing change */
        char          req_minor;     /* minor event code of event causing change */
    } XkbControlsNotifyEvent;