---
name: "XGetDeviceControl"
section: "3x"
platform: "linux"
package: "libxi-dev"
version: "4.3.0.dfsg.1-14sarge7"
release: "Debian 3.1 (Sarge)"
platforms: ["linux"]
url: "https://new.carta.tech/XGetDeviceControl/3x"
---

# XGetDeviceControl(3x)

query and change input device controls

## 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 *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 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.

## SEE ALSO

*Programming With Xlib*