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XIFreeDeviceInfo

NAME

XIQueryDevice, XIFreeDeviceInfo - get information about devices.

SYNOPSIS

 #include <X11/extensions/XInput2.h>
 

 XIDeviceInfo* XIQueryPointer( 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
 

 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;
 } XIValuatorInfo;
 

 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.
 

 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.