XGetDeviceControl(3)

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 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 sup-
       port 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  XOpen-
                   InputDevice.   This  error  may  also  occur  if some other
                   client has caused the specified device to become the X key-
                   board  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

X Version 11                      libXi 1.0.2          XGetDeviceControl(3X11)