XQueryDeviceState(X3xi) X Version 11 (Release 6.1)
XQueryDeviceState --
query the state of an extension input device.
Synopsis
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.
References
Xlib - C Language X Interface
UnixWare 7 BL14 Release -- October 1997
© 1997 The Santa Cruz Operation, Inc. All rights reserved.