XGetDeviceControl(3)       X FUNCTIONS       XGetDeviceControl(3)



NAME
       XGetDeviceControl, XChangeDeviceControl - query and change
       input device controls

SYNTAX
       XDeviceControl *XGetDeviceControl(Display  *display,  XDe-
              vice *device, int *controlType);

       int    XChangeDeviceControl(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



X Version 11               libXi 1.1.3       XGetDeviceControl(3)