XGetDeviceControl(3X11) X FUNCTIONS XGetDeviceControl(3X11)NAME
XGetDeviceControl, XChangeDeviceControl - query and change
input device controls
SYNTAX
XDeviceControl * XGetDeviceControl(display, device,
control)
Display *display;
XDevice *device;
int *controlType;
int XChangeDeviceControl(display, device, controlType,
control)
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.
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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
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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
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