xref: /xsrc/external/mit/libXi/dist/man/XGetDeviceControl.txt

XGETDEVICECONTROL(libmansuffix)
===============================

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.