NAME

       XGetDeviceControl, XChangeDeviceControl - query and change input device controls

SYNOPSIS

       #include <X11/extensions/XInput.h>

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

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

       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 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
                  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.

                                            09/15/2021                       XGETDEVICECONTROL(3)