XGetDeviceControl(3X11)

NAME
       XGetDeviceControl, XChangeDeviceControl - query and change
       input device controls

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

       int   XChangeDeviceControl(display,  device,  controlType,
       control)
             Display *display;
             XDevice *device;
             int controlType;
             XDeviceControl *control;

ARGUMENTS
       display        Specifies the connection to the X server.

       device         Specifies the device whose control is to be
                      interrogated or modified.

       controlType    Specifies  the type of control to be inter-
                      rogated 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 XDe-
       viceControl 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 iden-
       tified  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  XIn-
       put.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 informa-
       tion 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  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.

       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 XDeviceControl 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