XQueryDeviceState(3X11)XQueryDeviceState(3X11)NAMEXQueryDeviceState - query the state of an extension input device.
SYNOPSIS
XQueryDeviceState(display, device)
Display *display;
XDevice *device;
ARGUMENTS
Specifies the connection to the X server. 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
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
XQueryDeviceState(3X11)
