XGETDEVICEPROPERTY(3) libXi XGETDEVICEPROPERTY(3)NAME
XGetDeviceProperty, XChangeDeviceProperty, XDeleteDeviceProperty - Get,
change or delete a device's property.
SYNTAX
#include <X11/extensions/XInput.h>
int XGetDeviceProperty(Display *display, XDevice *device,
Atom property, long offset, long length,
Bool delete, Bool pending, Atom req_type,
Atom *actual_type_return,
int *actual_format_return,
unsigned long *nitems_return,
unsigned long *bytes_after_return,
unsigned char **prop_return);
void XChangeDeviceProperty(Display *display, XDevice *device,
Atom property, Atom type, int format,
int mode, const char *data, int nelements);
void XDeleteDeviceProperty(Display *display, XDevice *device,
Atom property);
ARGUMENTS
actual_type_return
Returns an atom identifier that defines the actual type of the
property.
actual_format_return
Returns the actual format of the property.
bytes_after_return
Returns the number of bytes remaining to be read in the property if
a partial read was performed.
data
Specifies the property data.
delete
Specifies a Boolean value that determines wether the property is
deleted.
display
Specifies the connection to the X server.
device
The device to grab.
format
Specifies whether the data should be viewed as a list of 8-bit,
16-bit, or 32-bit quantities. Possible values are 8, 16, and 32.
This information allows the X server to correctly perform byte-swap
operations as necessary. If the format is 16-bit or 32-bit, you must
explicitly cast the data pointer to an (unsigned char*) in the call
to XChangeDeviceProperty.
length
Specifies the length in 32-bit multiplies of the data to be
retrieved.
mode
Specifies the mode of operation. You can pass PropModeReplace,
PropModePrepend, or PropModeAppend.
nelements
Specifies the number of elements in data.
nitems_return
Returns the actual number of 8-bit, 16-bit, or 32-bit items stored
in the prop_return array.
num_values
Specifies the number of elements in the values list.
offset
Specifies the offset in the specified property (in 32-bit
quantities) where the data is to be retrieved.
pending
Specifies whether to retrieve the pending state of the property or
the current state.
property
Specifies the property to modify or query.
prop_return
Returns the data in the specified format. If the returned format is
8, the returned data is represented as a char array. If the returned
format is 16, the returned data is represented as an array of short
int type and should be cast to that type to obtain the elements. If
the returned format is 32, the property data will be stored as an
array of longs (which in a 64-bit application will be 64-bit values
that are padded in the upper 4 bytes).
req_type
Specifies the atom identifier associated with the property type or
AnyPropertyType.
DESCRIPTION
The XGetDeviceProperty function returns the actual type of the
property; the actual format of the property; the number of 8-bit,
16-bit, or 32-bit items transferred; the number of bytes remaining to
be read in the property; and a pointer to the data actually returned.
For a detailed description of this function, see the man page to
XGetWindowProperty.
The XChangeDeviceProperty function alters the property for the
specified device and causes the server to generate a
XPropertyNotifyEvent event on that device. For a detailed description
of this function, see the man page to XChangeProperty.
The XDeleteDeviceProperty function deletes the specified device
property. Note that a client cannot delete a property created by a
driver or the server. Attempting to do so will result in a BadAtom
error.
XGetDeviceProperty can generate a BadAtom, BadDevice error.
XChangeDeviceProperty can generate a BadDevice, a BadMatch, a BadAtom,
and a BadValue error.
XDeleteDeviceProperty can generate a BadDevice, and a BadAtom error.
DIAGNOSIS
BadAtom
A value does not describe a valid named identifier or the client
attempted to remove a driver-allocated property.
BadDevice
An invalid device was specified. The device does not exist.
SEE ALSO
XListDeviceProperties, XQueryDeviceProperty, XConfigureDeviceProperty.
AUTHOR
Peter Hutterer
Specification and implementation.
July 9, 2008 XGETDEVICEPROPERTY(3)
