XQueryDeviceState(3X11) X Version 11(Release 5) 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;
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XQueryDeviceState(3X11) X Version 11(Release 5) XQueryDeviceState(3X11)
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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