XGetFeedbackControl
XGetFeedbackControl(3X11) X FUNCTIONS XGetFeedbackControl(3X11)
NAME
XGetFeedbackControl, XChangeFeedbackControl - query and change input
device feedbacks
SYNTAX
XFeedbackState *XGetFeedbackControl(Display *display, XDevice *device,
int *num_feedbacks);
int XChangeFeedbackControl(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 XFeedbackControl 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 feedbacks. Whether or not a given
device supports feedbacks can be determined by examining the informa-
tion returned by the XOpenDevice request. For those devices that sup-
port 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 XFeed-
backState 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: KbdFeedback-
Class, 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. XFeedback-
State 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 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 XFeedback-
Control 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.
SEE ALSO
Programming With Xlib
XGetFeedbackControl(3X11)
