XQueryDeviceState(3X11) X FUNCTIONS XQueryDeviceState(3X11)NAMEXQueryDeviceState - 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 repre-
sented 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 FUNCTIONS 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 speci-
fied 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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