#include <X11/extensions/XInput.h>
XFeedbackState *XGetFeedbackControl( Display *display,
XDevice *device,
int *num_feedbacks);
int XChangeFeedbackControl( Display *display,
XDevice *device,
Mask mask,
XFeedbackControl *control);
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 thedevice is to be returned.
mask
Specifies a mask specific to each type of feedback that
describes howthe feedback is to be modified.
control
Specifies the address of an XFeedbackControl structure
that containsthe new values for the feedback.
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 feedbacks. 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: KbdFeedbackClass, PtrFeedbackClass, StringFeedbackClass, IntegerFeedbackClass, LedFeedbackClass, and BellFeedbackClass. 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 XChangeFeedbackControl 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 structure 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 specific 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;
BadDevice
An invalid device was specified. The specified 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
combination 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.