1XOPENDEVICE(3) XOPENDEVICE(3)
2
6 XOpenDevice, XCloseDevice - open or close an extension input device
7
9 #include <X11/extensions/XInput.h>
10 XDevice *XOpenDevice( Display *display,
12 XID device_id);
13 XCloseDevice( Display *display,
15 XDevice *device);
16 display
18 Specifies the connection to the X server.
19 device_id
21 Specifies the id of the device to be opened
22 device
24 Specifies the device to be closed
25
27 The XOpenDevice request makes an input device accessible to a
28 client through input extension protocol requests. If
29 successful, it returns a pointer to an XDevice structure.
30 The XCloseDevice request makes an input device inaccessible to
32 a client through input extension protocol requests. Before
33 terminating, and client that has opened input devices through
34 the input extension should close them via CloseDevice.
35 When a client makes an XCloseDevice request, any active grabs
37 that the client has on the device are released. Any event
38 selections that the client has are deleted, as well as any
39 passive grabs. If the requesting client is the last client
40 accessing the device, the server may disable all access by X to
41 the device.
42 XOpenDevice and XCloseDevice can generate a BadDevice error.
44 Structures
46 The XDevice structure returned by XOpenDevice contains:
48 typedef struct {
49 XID device_id;
50 int num_classes;
51 XInputClassInfo *classes;
52 } XDevice;
53 The classes field is a pointer to an array of XInputClassInfo
55 structures. Each element of this array contains an event type
56 base for a class of input supported by the specified device.
57 The num_classes field indicates the number of elements in the
58 classes array.
59 The XInputClassInfo structure contains:
61 typedef struct {
63 unsigned char input_class;
64 unsigned char event_type_base;
65 } XInputClassInfo;
66 The input_class field identifies one class of input supported
68 by the device. Defined types include KeyClass, ButtonClass,
69 ValuatorClass, ProximityClass, FeedbackClass, FocusClass, and
70 OtherClass. The event_type_base identifies the event type of
71 the first event in that class.
72 The information contained in the XInputClassInfo structure is
74 used by macros to obtain the event classes that clients use in
75 making XSelectExtensionEvent requests. Currently defined macros
76 include DeviceKeyPress, DeviceKeyRelease, DeviceButtonPress,
77 DeviceButtonRelease, DeviceMotionNotify, DeviceFocusIn,
78 DeviceFocusOut, ProximityIn, ProximityOut, DeviceStateNotify,
79 DeviceMappingNotify, ChangeDeviceNotify,
80 DevicePointerMotionHint, DeviceButton1Motion,
81 DeviceButton2Motion, DeviceButton3Motion, DeviceButton4Motion,
82 DeviceButton5Motion, DeviceButtonMotion, DeviceOwnerGrabButton,
83 DeviceButtonPressGrab, and NoExtensionEvent.
84 To obtain the proper event class for a particular device, one
86 of the above macros is invoked using the XDevice structure for
87 that device. For example,
88 DeviceKeyPress (*device, type, eventclass);
89 returns the DeviceKeyPress event type and the eventclass for
91 DeviceKeyPress events from the specified device.
92 This eventclass can then be used in an XSelectExtensionEvent
94 request to ask the server to send DeviceKeyPress events from
95 this device. When a selected event is received via XNextEvent,
96 the type can be used for comparison with the type in the event.
97
99 BadDevice
100 An invalid device was specified. The specified device
101 does not exist, or is the X keyboard or X pointer. This
102 error may also occur if some other client has caused the
103 specified device to become the X keyboard or X pointer
104 device via the XChangeKeyboardDevice or
105 XChangePointerDevice requests.
106 09/15/2021 XOPENDEVICE(3)