XGETFEEDBACKCONTROL
XGETFEEDBACKCONTROL
NAMESYNOPSIS
DESCRIPTION
DIAGNOSTICS
NAME
XGetFeedbackControl, XChangeFeedbackControl − query and change input device feedbacks
SYNOPSIS
#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.
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 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;
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
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.
Opportunity
Personal Opportunity - Free software gives you access to billions of dollars of software at no cost. Use this software for your business, personal use or to develop a profitable skill. Access to source code provides access to a level of capabilities/information that companies protect though copyrights. Open source is a core component of the Internet and it is available to you. Leverage the billions of dollars in resources and capabilities to build a career, establish a business or change the world. The potential is endless for those who understand the opportunity.
Business Opportunity - Goldman Sachs, IBM and countless large corporations are leveraging open source to reduce costs, develop products and increase their bottom lines. Learn what these companies know about open source and how open source can give you the advantage.
Free Software
Free Software provides computer programs and capabilities at no cost but more importantly, it provides the freedom to run, edit, contribute to, and share the software. The importance of free software is a matter of access, not price. Software at no cost is a benefit but ownership rights to the software and source code is far more significant.
Free Office Software - The Libre Office suite provides top desktop productivity tools for free. This includes, a word processor, spreadsheet, presentation engine, drawing and flowcharting, database and math applications. Libre Office is available for Linux or Windows.
Free Books
The Free Books Library is a collection of thousands of the most popular public domain books in an online readable format. The collection includes great classical literature and more recent works where the U.S. copyright has expired. These books are yours to read and use without restrictions.
Source Code - Want to change a program or know how it works? Open Source provides the source code for its programs so that anyone can use, modify or learn how to write those programs themselves. Visit the GNU source code repositories to download the source.
Education
Study at Harvard, Stanford or MIT - Open edX provides free online courses from Harvard, MIT, Columbia, UC Berkeley and other top Universities. Hundreds of courses for almost all major subjects and course levels. Open edx also offers some paid courses and selected certifications.
Linux Manual Pages - A man or manual page is a form of software documentation found on Linux/Unix operating systems. Topics covered include computer programs (including library and system calls), formal standards and conventions, and even abstract concepts.
