225 lines
8.4 KiB
Plaintext
225 lines
8.4 KiB
Plaintext
XLISTINPUTDEVICES(libmansuffix)
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===============================
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NAME
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----
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XListInputDevices, XFreeDeviceList - list available input
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devices
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SYNOPSIS
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--------
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#include <X11/extensions/XInput.h>
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XDeviceInfo *XListInputDevices( Display *display,
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int *ndevices_return);
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int XFreeDeviceList( XDeviceInfo *list);
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display
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Specifies the connection to the X server.
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ndevices_return
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Specifies a pointer to a variable where the number of
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available devices canbe returned.
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list
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Specifies the list of devices to free. The
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XFreeDeviceList functionfrees the list of available
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extension input devices.
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DESCRIPTION
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-----------
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The XListInputDevices request lists the available input
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devices. This list includes the core keyboard and any physical
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input device currently accessible through the X server, and any
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input devices that are not currently accessible through the X
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server but could be accessed if requested.
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A master pointer is a virtual pointer device that does not
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represent a physical device. It is visually represented through
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a cursor. A master keyboard is a virtual keyboard device that
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does not represent a physical device. It is virtually
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representd through a keyboard focus. A master pointer and a
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master keyboard are always paired (i.e. if shift is pressed on
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the master keyboard, a pointer click would be a shift-click).
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Multiple master pointer/keyboard pairs can exist.
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X servers supporting the X Input Extension version 2,
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XListInputDevices only returns the first master pointer, the
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first master keyboard and all slave devices. Additional master
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devices are not listed.
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Physical devices (so-called slave devices) are attached to
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either a master pointer or a master keyboard, depending on
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their capabilities. If a slave device generates an event, the
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event is also generated by the respective master device.
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Multiple slave devices can be attached to a single master
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device.
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Some server implementations may make all physical input devices
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available at the time the server is initialized. Others may
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wait until requested by a client to access an input device. In
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the latter case, it is possible that an input device will be
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listed as available at one time but not at another.
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For each input device available to the server, the
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XListInputDevices request returns an XDeviceInfo structure.
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That structure contains a pointer to a list of structures, each
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of which contains information about one class of input
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supported by the device. The XDeviceInfo structure is defined
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as follows:
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typedef struct _XDeviceInfo {
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XID id;
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Atom type;
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char *name;
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int num_classes;
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int use;
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XAnyClassPtr inputclassinfo;
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} XDeviceInfo;
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The id is a number in the range 0-128 that uniquely identifies
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the device. It is assigned to the device when it is initialized
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by the server.
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The type field is of type Atom and indicates the nature of the
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device. The type will correspond to one of the following strings
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(defined in the header file XI.h):
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XI_MOUSE XI_TABLET XI_KEYBOARD XI_TOUCHSCREEN XI_TOUCHPAD
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XI_BUTTONBOX XI_BARCODE XI_TRACKBALL XI_QUADRATURE XI_ID_MODULE
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XI_ONE_KNOB XI_NINE_KNOB XI_KNOB_BOX XI_SPACEBALL XI_DATAGLOVE
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XI_EYETRACKER XI_CURSORKEYS XI_FOOTMOUSE XI_JOYSTICK
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These strings may be used in an XInternAtom request to return
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an atom that can be compared with the type field of the
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XDeviceInfo structure.
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The name field contains a pointer to a null-terminated string
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that serves as identifier of the device. This identifier may be
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user-configured or automatically assigned by the server.
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The num_classes field is a number in the range 0-255 that
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specifies the number of input classes supported by the device
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for which information is returned by ListInputDevices. Some
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input classes, such as class Focus and class Proximity do not
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have any information to be returned by ListInputDevices.
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All devices provide an AttachClass. This class specifies the
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master device a given slave device is attached to. For master
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devices, the class specifies the respective paired master
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device.
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The use field specifies how the device is currently being used.
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If the value is IsXKeyboard, the device is a master keyboard.
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If the value is IsXPointer, the device is a master pointer. If
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the value is IsXExtensionPointer, the device is a slave
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pointer. If the value is IsXExtensionKeyboard, the device is a
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slave keyboard. If the value is IsXExtensionDevice, the device
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is available for use as an extension device.
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The inputclassinfo field contains a pointer to the first
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input-class specific data. The first two fields are common to
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all classes.
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The class field is a number in the range 0-255. It uniquely
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identifies the class of input for which information is
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returned. Currently defined classes are KeyClass, ButtonClass,
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and ValuatorClass.
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The length field is a number in the range 0- 255. It specifies
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the number of bytes of data that are contained in this input
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class. The length includes the class and length fields.
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The XKeyInfo structure describes the characteristics of the
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keys on the device. It is defined as follows:
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typedef struct _XKeyInfo {
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XID class;
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int length;
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unsigned short min_keycode;
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unsigned short max_keycode;
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unsigned short num_keys;
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} XKeyInfo;
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min_keycode is of type KEYCODE. It specifies the minimum
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keycode that the device will report. The minimum keycode will
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not be smaller than 8.
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max_keycode is of type KEYCODE. It specifies the maximum
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keycode that the device will report. The maximum keycode will
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not be larger than 255.
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num_keys specifies the number of keys that the device has.
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The XButtonInfo structure defines the characteristics of the
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buttons on the device. It is defined as follows:
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typedef struct _XButtonInfo {
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XID class;
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int length;
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short num_buttons;
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} XButtonInfo;
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num_buttons specifies the number of buttons that the device
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has.
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The XValuatorInfo structure defines the characteristics of the
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valuators on the device. It is defined as follows:
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typedef struct _XValuatorInfo {
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XID class;
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int length;
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unsigned char num_axes;
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unsigned char mode;
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unsigned long motion_buffer;
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XAxisInfoPtr axes;
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} XValuatorInfo;
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num_axes contains the number of axes the device supports.
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mode is a constant that has one of the following values:
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Absolute or Relative. Some devices allow the mode to be changed
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dynamically via the SetDeviceMode request.
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motion_buffer_size is a cardinal number that specifies the
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number of elements that can be contained in the motion history
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buffer for the device.
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The axes field contains a pointer to an XAxisInfo structure.
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The XAxisInfo structure is defined as follows:
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typedef struct _XAxisInfo {
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int resolution;
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int min_value;
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int max_value;
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} XAxisInfo;
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The resolution contains a number in counts/meter.
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The min_val field contains a number that specifies the minimum
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value the device reports for this axis. For devices whose mode
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is Relative, the min_val field will contain 0.
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The max_val field contains a number that specifies the maximum
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value the device reports for this axis. For devices whose mode
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is Relative, the max_val field will contain 0.
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The XAttachInfo structure is defined as follows:
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typedef struct _XAttachInfo {
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int attached;
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} XAttachInfo;
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If the device is a slave device, attached specifies the device
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ID of the master device this device is attached to. If the
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device is not attached to a master device, attached is
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Floating. If the device is a master device, attached specifies
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the device ID of the master device this device is paired with.
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To free the XDeviceInfo array created by XListInputDevices, use
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XFreeDeviceList.
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