Provided by: libxi-dev_1.6.0-0ubuntu2_amd64 bug

NAME

       XIQueryDevice, XIFreeDeviceInfo - get information about devices.

SYNOPSIS

       #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.

DESCRIPTION

           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.

DIAGNOSTICS

           BadDevice
                  An invalid device was specified. The device does not
                  exist or is not a pointer device.