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.\" Title: xgetdeviceproperty
.\" Author: [FIXME: author] [see http://docbook.sf.net/el/author]
.\" Generator: DocBook XSL Stylesheets v1.77.1
.\" Date: 03/09/2013
.\" Manual: \ \&
.\" Source: \ \&
.\" Language: English
.\"
.TH "XGETDEVICEPROPERTY" "3" "03/09/2013" "\ \&" "\ \&"
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.SH "NAME"
XGetDeviceProperty, XChangeDeviceProperty, XDeleteDeviceProperty \- Get, change or delete a device\*(Aqs property\&.
.SH "SYNOPSIS"
.sp
.nf
#include
.fi
.sp
.nf
int XGetDeviceProperty( Display *display,
XDevice *device,
Atom property,
long offset,
long length,
Bool delete,
Atom req_type,
Atom *actual_type_return,
int *actual_format_return,
unsigned long *nitems_return,
unsigned long *bytes_after_return,
unsigned char **prop_return)
.fi
.sp
.nf
void XChangeDeviceProperty( Display *display,
XDevice *device,
Atom property,
Atom type,
int format,
int mode,
const char *data,
int nelements)
.fi
.sp
.nf
void XDeleteDeviceProperty( Display *display,
XDevice *device,
Atom property)
.fi
.sp
.nf
actual_type_return
Returns an atom identifier that defines the actual type
of the property\&.
.fi
.sp
.nf
actual_format_return
Returns the actual format of the property\&.
.fi
.sp
.nf
bytes_after_return
Returns the number of bytes remaining to be read in the
property if a partial read was performed\&.
.fi
.sp
.nf
data
Specifies the property data\&.
.fi
.sp
.nf
delete
Specifies a Boolean value that determines whether the
property is deleted\&.
.fi
.sp
.nf
display
Specifies the connection to the X server\&.
.fi
.sp
.nf
device
The device to grab\&.
.fi
.sp
.nf
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\&.
.fi
.sp
.nf
length
Specifies the length in 32\-bit multiplies of the data to
be retrieved\&.
.fi
.sp
.nf
mode
Specifies the mode of operation\&. You can pass
PropModeReplace, PropModePrepend, or PropModeAppend\&.
.fi
.sp
.nf
nelements
Specifies the number of elements in data\&.
.fi
.sp
.nf
nitems_return
Returns the actual number of 8\-bit, 16\-bit, or 32\-bit
items stored in the prop_return array\&.
.fi
.sp
.nf
num_values
Specifies the number of elements in the values list\&.
.fi
.sp
.nf
offset
Specifies the offset in the specified property (in
32\-bit quantities) where the data is to be retrieved\&.
.fi
.sp
.nf
property
Specifies the property to modify or query\&.
.fi
.sp
.nf
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)\&.
.fi
.sp
.nf
req_type
Specifies the atom identifier associated with the
property type or AnyPropertyType\&.
.fi
.SH "DESCRIPTION"
.sp
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\&.
.sp
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\&.
.sp
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\&.
.sp
XGetDeviceProperty can generate a BadAtom, BadDevice error\&.
.sp
XChangeDeviceProperty can generate a BadDevice, a BadMatch, a BadAtom, and a BadValue error\&.
.sp
XDeleteDeviceProperty can generate a BadDevice, and a BadAtom error\&.
.SH "DIAGNOSIS"
.sp
.if n \{\
.RS 4
.\}
.nf
BadAtom
A value does not describe a valid named identifier or
the client attempted to remove a driver\-allocated
property\&.
.fi
.if n \{\
.RE
.\}
.sp
.if n \{\
.RS 4
.\}
.nf
BadDevice
An invalid device was specified\&. The device does not
exist\&.
.fi
.if n \{\
.RE
.\}
.SH "SEE ALSO"
.sp
.if n \{\
.RS 4
.\}
.nf
XListDeviceProperties(3)
.fi
.if n \{\
.RE
.\}