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XIQUERYDEVICE(3) XIQUERYDEVICE(3) 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. 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 attachment. - 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, XIGestureClass. 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. 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 minimum 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 { 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 occurred. 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. typedef struct { int type; int sourceid; 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. 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. 09/15/2021 XIQUERYDEVICE(3)