XGetDeviceControl

XGetDeviceControl(3X11)		 X FUNCTIONS	      XGetDeviceControl(3X11)



NAME
       XGetDeviceControl,  XChangeDeviceControl	 -  query  and	change	input
       device controls

SYNTAX
       XDeviceControl *XGetDeviceControl(Display *display,  XDevice  *device,
	      int *controlType);

       int  XChangeDeviceControl(Display  *display, XDevice *device, int con-
	      trolType, XDeviceControl *control);

ARGUMENTS
       display	      Specifies the connection to the X server.

       device	      Specifies the device whose control is  to	 be  interro-
		      gated or modified.

       controlType    Specifies	 the  type  of	control to be interrogated or
		      changed.

       control	      Specifies the address of	an  XDeviceControl  structure
		      that contains the new values for the Device.

DESCRIPTION
       These  requests	are  provided  to manipulate those input devices that
       support device control.	A BadMatch error will  be  generated  if  the
       requested device does not support any device controls.

       Valid  device  control  types  that  can	 be  used with these requests
       include the following:

       DEVICE_RESOLUTION   Queries or changes the resolution of valuators  on
			   input devices.

       The  XGetDeviceControl  request returns a pointer to an XDeviceControl
       structure.

       XGetDeviceControl can generate a BadDevice or BadMatch error.

       The XChangeDeviceControl request modifies the values of one control on
       the  specified  device.	 The control is identified by the id field of
       the XDeviceControl structure that is passed with the request.

       XChangeDeviceControl can generate a BadDevice, BadMatch,	 or  BadValue
       error.

STRUCTURES
       Each  control  is  described  by a structure specific to that control.
       These structures are defined in the file XInput.h.

       XDeviceControl is a generic structure that contains  two	 fields	 that
       are at the beginning of each class of control:

       typedef struct {
	    XID class;
	    int length;
       } XDeviceControl;

       The  XDeviceResolutionState  structure defines the information that is
       returned for device resolution for devices with valuators.

       typedef struct {
	    XID	    control;
	    int	    length;
	    int	    num_valuators;
	    int	    *resolutions;
	    int	    *min_resolutions;
	    int	    *max_resolutions;
       } XDeviceResolutionState;

       The XDeviceResolutionControl structure defines the attributes that can
       be controlled for keyboard Devices.

       typedef struct {
	    XID	    control;
	    int	    length;
	    int	    first_valuator;
	    int	    num_valuators;
	    int	    *resolutions;
       } XDeviceResolutionControl;

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.

       BadMatch	   This error may occur if an XGetDeviceControl	 request  was
		   made	 specifying  a	device	that  has  no  controls or an
		   XChangeDeviceControl request was made with an  XDeviceCon-
		   trol	 structure  that contains an invalid Device type.  It
		   may also occur if an invalid combination of mask  bits  is
		   specified  (DvKey  but  no  DvAutoRepeatMode	 for keyboard
		   Devices), or if an  invalid	KeySym	is  specified  for  a
		   string Device.

       BadValue	   Some	 numeric  value	 falls	outside	 the  range of values
		   accepted by the XChangeDeviceControl	 request.   Unless  a
		   specific  range  is	specified  for	an argument, the full
		   range defined by the argument’s  type  is  accepted.	  Any
		   argument  defined  as  a  set of alternatives can generate
		   this error.

SEE ALSO
       Programming With Xlib



						      XGetDeviceControl(3X11)