XQueryDeviceState(3) X FUNCTIONS XQueryDeviceState(3)
NAME
XQueryDeviceState - query the state of an extension input device.
SYNTAX
int XQueryDeviceState(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 (cur-
rent 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 rela-
tive 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 XOpen-
InputDevice. This error may also occur if some other
client has caused the specified device to become the X key-
board or X pointer device via the XChangeKeyboardDevice or
XChangePointerDevice requests.
SEE ALSO
Programming with Xlib
X Version 11 libXi 1.2.1 XQueryDeviceState(3)
Mac OS X 10.6 X11 - Generated Sun Mar 7 12:30:40 CST 2010