XQueryDeviceState.3X11.gz(3X11)



XQueryDeviceState(3X11)       SDK X11 R4.11MU05      XQueryDeviceState(3X11)


NAME
       XQueryDeviceState - query the state of an extension input device.

SYNTAX
       XQueryDeviceState(display, device)
             Display *display;
             XDevice *device;

ARGUMENTS
       display     Specifies the connection to the X server.

       device      Specifies the device whose state is to be queried.

DESCRIPTION
       The XQueryDeviceState request queries the state of an input device.
       The current state of keys and buttons (up or down), and valuators
       (current value) on the device is reported by this request.  Each key
       or button is represented by a bit in the XDeviceState structure that
       is returned.  Valuators on the device report 0 if they are reporting
       relative information, and the current value if they are reporting
       absolute information.

       XQueryDeviceState can generate a BadDevice error.

STRUCTURES
       The XDeviceState structure contains:

       typedef struct {
            XID device_id;
            int num_classes;
            XInputClass *data;
       } XDeviceState;

       The XValuatorState structure contains:

       typedef struct {
            unsigned char class;
            unsigned char length;
            unsigned char num_valuators;
            unsigned char mode;
            int *valuators;
       } XValuatorState;

       The XKeyState structure contains:

       typedef struct {
            unsigned char class;
            unsigned char length;
            short         num_keys;
            char keys[32];
       } XKeyState;

       The XButtonState structure contains:

       typedef struct {
            unsigned char class;
            unsigned char length;
            short         num_buttons;
            char buttons[32];
       } XButtonState;

DIAGNOSTICS
       BadDevice   An invalid device was specified.  The specified device
                   does not exist or has not been opened by this client via
                   XOpenInputDevice.  This error may also occur if some
                   other client has caused the specified device to become
                   the X keyboard or X pointer device via the
                   XChangeKeyboardDevice or XChangePointerDevice requests.

SEE ALSO
       Programming with Xlib


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