NAME
SYNOPSIS
DESCRIPTION
DIAGNOSTICS
XIQueryDevice, XIFreeDeviceInfo − get information about devices.
#include <X11/extensions/XInput2.h>
XIDeviceInfo*
XIQueryDevice( Display *display,
int deviceid,
int *ndevices_return);
XIFreeDeviceInfo( XIDeviceInfo *info);
deviceid
Specifies the device to query or XIAllDevices or
XIAllMasterDevices.
display
Specifies the connection to the X server.
ndevices_return
Returns the number of devices returned.
info
A list of device XIDeviceInfo structs to be freed.
The
XIQueryDevice returns information about one or more input
devices. If the deviceid specifies a device, ndevices_return
is
1 and the returned information describes only the requested
device. If deviceid is XIAllDevices or XIAllMasterDevices,
ndevices_return is the number of devices or master devices,
respectively, and the returned information represents all
devices or all master devices, respectively.
To free the
XIDeviceInfo array returned by XIQueryDevice, use
XIFreeDeviceInfo.
For each input
device requested, the XIQueryDevice returns an
XIDeviceInfo structure. Each structure contains information
about the capabilities of one input device available to the
server.
typedef struct
{
int deviceid;
char *name;
int use;
int attachment;
Bool enabled;
int num_classes;
XIAnyClassInfo **classes;
} XIDeviceInfo;
The deviceid is
the numeric unique id of the device. A deviceid
is unique for the life−time of a device but a server
may re−use
the id once a device has been removed.
The name points
to a null−terminated string specifying the
identifier of the device.
The use and
attachment fields specify the type of the device
and the current attachment or pairing.
− If use is XIMasterPointer, the device is a master
pointer and
attachment specifies the deviceid of the paired master
keyboard.
− If use is XIMasterKeyboard, the device is a master
keyboard,
and the attachment field specifies the paired master
pointer.
− If use is XISlavePointer, the device is a slave
device and
currently attached to the master pointer specified in
attachement.
− If use is XISlaveKeyboard, the device is a slave
device an
currently attached to the master keyboard specified in
attachment.
− If use is XIFloatingSlave, the device is a slave
device
currently not attached to any master device. The value of
the
attachment field for floating slave devices is
undefined.
The enabled
field specifies if the device is currently enabled
and can send events. Disabled devices will not send
events.
The num_classes
field specifies the number of input classes
pointed to by classes. The first two fields of all input
classes are identical.
typedef struct
{
int type;
int sourceid;
} XIAnyClassInfo;
The type field
specifies the type of the input class.
Currently, the following types are defined:
XIKeyClass, XIButtonClass, XIValuatorClass, XIScrollClass,
XITouchClass
In the future,
additional types may be added. Clients are
required to ignore unknown input classes.
The sourceid is
the deviceid this class originated from. For
master devices, the sourceid is typically the id of the
slave
device currently sending events. For slave devices, the
sourceid is typically the device's id.
A device may
have zero or one XIButtonClass, denoting the
device's capability to send button events.
typedef struct
{
int mask_len;
unsigned char *mask;
} XIButtonState;
typedef struct
{
int type;
int sourceid;
int num_buttons;
Atom *labels;
XIButtonState state;
} XIButtonClassInfo;
The num_buttons
field specifies the number of buttons available
on this device. A device that has an XIButtonClass must have
at
least one button.
labels is a
list of num_buttons Atoms specifying the button
labels for this device. If the label is not None, then the
label specifies the type of button in physical device order
(i.e. as the buttons are numbered on the physical input
device).
The state is
the current button state as seen by clients (i.e.
after button mapping is applied). The mask_len field
specifies
the length of mask in bytes. For each button on the device,
the
respective bit in mask is set if the button is currently
logically down.
A device may
have zero or one XIKeyClass, denoting the device's
capability to send key events.
typedef struct
{
int type;
int sourceid;
int num_keycodes;
int *keycodes;
} XIKeyClassInfo;
The
num_keycodes field specifies the number of keycodes
available on this device. A device that has an XIKeyClass
must
have at least one keycode.
keycodes is a
list of num_keycodes keycodes the device may
send.
A device may
have zero or more XIValuatorClass, denoting the
device's capability to send coordinates.
typedef struct
{
int type;
int sourceid;
int number;
Atom label;
double min;
double max;
double value;
int resolution;
int mode;
} XIValuatorClassInfo;
The number
field specifies the number of the axis on the
physical device.
If the label
field is not None, the value of label is an Atom
describing the axis.
min and max are
the minimum and maximum values allowed on this
axis. If both are zero, no minumum or maximum values are set
on
this device. value is the current value of this axis.
The resolution
field specifies the resolution of the device in
units/m.
The mode
specifies the mode of this axis. If the mode is
XIModeAbsolute this axis sends absolute coordinates. If the
mode is XIModeRelative, this device sends relative
coordinates.
typedef struct
{
int type;
int sourceid;
int number;
int scroll_type;
double increment;
int flags;
} XIScrollClassInfo;
This class
describes scrolling capability on a valuator. For
each XIScrollClassInfo, an XIValuatorClassInfo with the same
number is present on the device.
The number
field specifies the valuator number on the physical
device that this scroll information applies to. See the
respective XIValuatorClassInfo for detailed information on
this
valuator.
The scroll_type
field specifies the type of scrolling, either
XIScrollTypeVertical or XIScrollTypeHorizontal.
The increment
specifies the value change considered one unit of
scrolling down.
The flags field
specifies flags that apply to this scrolling
information:
If
XIScrollFlagNoEmulation is set, the server will not
emulate legacy button events for valuator changes on this
valuator.
If
XIScrollFlagPreferred is set, this axis is the
preferred axis for this scroll type and will be used for
the emulation of XI_Motion events when the driver submits
legacy scroll button events.
typedef struct
{
int type;
int sourceid;
int mode;
int num_touches;
} XITouchClassInfo;
A device may
have zero or one XITouchClassInfo, denoting
multi−touch capability on the device. A device with a
XITouchClassInfo
may send TouchBegin, TouchUpdate, TouchEnd and
TouchOwnership events.
The mode field
is either XIDirectTouch for direct−input touch devices
such as touchscreens or XIDependentTouch for indirect input
devices such
as touchpads. For XIDirectTouch devices, touch events are
sent to window
at the position the touch occured. For XIDependentTouch
devices, touch
events are sent to the window at the position of the
device's sprite.
The num_touches
field defines the maximum number of simultaneous touches
the device supports. A num_touches of 0 means the maximum
number of
simultaneous touches is undefined or unspecified. This field
should be
used as a guide only, devices will lie about their
capabilities.
A device with
an XITouchClassInfo may still send pointer events. The
valuators must be defined with the respective
XIValuatorClass
classes. A valuator may send both pointer and
touch−events.
XIQueryDevice can generate a BadDevice error.
XIFreeDeviceInfo
frees the information returned by
XIQueryDevice.
BadDevice
An invalid device was specified. The device does not
exist or is not a pointer device.