centos man page for xquerydevicestate

XQUERYDEVICESTATE(3)													      XQUERYDEVICESTATE(3)

NAME
       XQueryDeviceState - query the state of an extension input device.

SYNOPSIS
       #include <X11/extensions/XInput.h>

       XDeviceState* XQueryDeviceState( Display *display,
					XDevice *device);

       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.

								    03/09/2013						      XQUERYDEVICESTATE(3)