XGetFeedbackControl(3X11)
NAME
XGetFeedbackControl, XChangeFeedbackControl - query and
change input device feedbacks
SYNTAX
XFeedbackState * XGetFeedbackControl(display, device,
num_feedbacks)
Display *display;
XDevice *device;
int *num_feedbacks;
int XChangeFeedbackControl(display, device, mask, control)
Display *display;
XDevice *device;
Mask mask;
XFeedbackControl *control;
ARGUMENTS
display Specifies the connection to the X server.
device Specifies the device whose feedbacks are to
be queried or modified.
num_feedbacks Specifies an address into which the number
of feedbacks supported by the device is to
be returned.
mask Specifies a mask specific to each type of
feedback that describes how the feedback is
to be modified.
control Specifies the address of an XFeedbackCon-
trol structure that contains the new values
for the feedback.
DESCRIPTION
These requests are provided to manipulate those input
devices that support feedbacks. A BadMatch error will be
generated if the requested device does not support feed-
backs. Whether or not a given device supports feedbacks
can be determined by examining the information returned by
the XOpenDevice request. For those devices that support
feedbacks, XOpenDevice will return an XInputClassInfo
structure with the input_class field equal to the constant
FeedbackClass (defined in the file XI.h).
The XGetFeedbackControl request returns a pointer to a
list of XFeedbackState structures. Each item in this list
describes one of the feedbacks supported by the device.
The items are variable length, so each contains its length
to allow traversal to the next item in the list.
The feedback classes that are currently defined are: Kbd-
FeedbackClass, PtrFeedbackClass, StringFeedbackClass,
IntegerFeedbackClass, LedFeedbackClass, and BellFeedback-
Class. These constants are defined in the file XI.h. An
input device may support zero or more classes of feedback,
and may support multiple feedbacks of the same class.
Each feedback contains a class identifier and an id that
is unique within that class for that input device. The id
is used to identify the feedback when making an XChange-
FeedbackControl request.
XGetFeedbackControl can generate a BadDevice or BadMatch
error.
The XChangeFeedbackControl request modifies the values of
one feedback on the specified device. The feedback is
identified by the id field of the XFeedbackControl struc-
ture that is passed with the request. The fields of the
feedback that are to be modified are identified by the
bits of the mask that is passed with the request.
XChangeFeedbackControl can generate a BadDevice, BadMatch,
or BadValue error.
STRUCTURES
Each class of feedback is described by a structure spe-
cific to that class. These structures are defined in the
file XInput.h. XFeedbackState and XFeedbackControl are
generic structures that contain three fields that are at
the beginning of each class of feedback:
typedef struct {
XID class;
int length;
XID id;
} XFeedbackState, XFeedbackControl;
The XKbdFeedbackState structure defines the attributes
that are returned for feedbacks equivalent to those on the
X keyboard.
typedef struct {
XID class;
int length;
XID id;
int click;
int percent;
int pitch;
int duration;
int led_mask;
int global_auto_repeat;
char auto_repeats[32];
} XKbdFeedbackState;
The XPtrFeedbackState structure defines the attributes
that are returned for feedbacks equivalent to those on the
the X pointer.
typedef struct {
XID class;
int length;
XID id;
int accelNum;
int accelDenom;
int threshold;
} XPtrFeedbackState;
The XIntegerFeedbackState structure defines attributes
that are returned for integer feedbacks.
typedef struct {
XID class;
int length;
XID id;
int resolution;
int minVal;
int maxVal;
} XIntegerFeedbackState;
The XStringFeedbackState structure defines the attributes
that are returned for string feedbacks.
typedef struct {
XID class;
int length;
XID id;
int max_symbols;
int num_syms_supported;
KeySym *syms_supported;
} XStringFeedbackState;
The XBellFeedbackState structure defines the attributes
that are returned for bell feedbacks.
typedef struct {
XID class;
int length;
XID id;
int percent;
int pitch;
int duration;
} XBellFeedbackState;
The XLedFeedbackState structure defines the attributes
that are returned for LED feedbacks.
typedef struct {
XID class;
int length;
XID id;
int led_values;
} XLedFeedbackState;
The XPrtFeedbackControl structure defines the attributes
that can be controlled for pointer feedbacks.
typedef struct {
XID class;
int length;
XID id;
int accelNum;
int accelDenom;
int threshold;
} XPtrFeedbackControl;
The XKbdFeedbackControl structure defines the attributes
that can be controlled for keyboard feedbacks.
typedef struct {
XID class;
int length;
XID id;
int click;
int percent;
int pitch;
int duration;
int led_mask;
int led_value;
int key;
int auto_repeat_mode;
} XKbdFeedbackControl;
The XStringFeedbackControl structure defines the
attributes that can be controlled for string feedbacks.
typedef struct {
XID class;
int length;
XID id;
int num_keysyms;
KeySym *syms_to_display;
} XStringFeedbackControl;
The XIntegerFeedbackControl structure defines the
attributes that can be controlled for integer feedbacks.
typedef struct {
XID class;
int length;
XID id;
int int_to_display;
} XIntegerFeedbackControl;
The XBellFeedbackControl structure defines the attributes
that can be controlled for bell feedbacks.
typedef struct {
XID class;
int length;
XID id;
int percent;
int pitch;
int duration;
} XBellFeedbackControl;
The XLedFeedbackControl structure defines the attributes
that can be controlled for LED feedbacks.
typedef struct {
XID class;
int length;
XID id;
int led_mask;
int led_values;
} XLedFeedbackControl;
DIAGNOSTICS
BadDevice An invalid device was specified. The speci-
fied device does not exist or has not been
opened by this client via XOpenInputDevice.
This error may also occur if some other client
has caused the specified device to become the
X keyboard or X pointer device via the
XChangeKeyboardDevice or XChangePointerDevice
requests.
BadMatch This error may occur if an XGetFeedbackControl
request was made specifying a device that has
no feedbacks, or an XChangeFeedbackControl
request was made with an XFeedbackControl
structure that contains an invalid feedback
type. It may also occur if an invalid combi-
nation of mask bits is specified (DvKey but no
DvAutoRepeatMode for keyboard feedbacks), or
if an invalid KeySym is specified for a string
feedback.
BadValue Some numeric value falls outside the range of
values accepted by the XChangeFeedbackControl
request. Unless a specific range is specified
for an argument, the full range defined by the
argument's type is accepted. Any argument
defined as a set of alternatives can generate
this error.
SEE ALSO
Programming With Xlib