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XICHANGEPROPERTY(3)					   XICHANGEPROPERTY(3)

NAME
       XIChangeProperty, XIGetProperty,	XIDeleteProperty - change, retrieve or
       delete a	device's property.

SYNOPSIS
       #include	<X11/extensions/XInput2.h>

       void XIChangeProperty( Display* dpy,
			      int deviceid,
			      Atom property,
			      Atom type,
			      int format,
			      int mode,
			      unsigned char *data,
			      int num_items)

       void XIDeleteProperty( Display *dpy,
			      int deviceid,
			      Atom property)

       Status XIGetProperty( Display *dpy,
			     int deviceid,
			     Atom property,
			     long offset,
			     long length,
			     Bool delete_property,
			     Atom type,
			     Atom *type_return,
			     int *format_return,
			     unsigned long *num_items_return,
			     unsigned long *bytes_after_return,
			     unsigned char **data)

       bytes_after_return
	      Returns the number of bytes remaining to be read in the prop-
	      erty if a	partial	read was performed.

       data
	      Specifies	the property data.

       display
	      Specifies	the connection to the X	server.

       delete_property
	      Specifies	a Boolean value	that determines	whether	the property
	      is to be deleted.

       deviceid
	      The device to list the properties	for.

       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 your
	      data pointer to an (unsigned char	*) in the call to
	      XIChangeProperty.

       format_return
	      Returns the actual format	of the property.

       length
	      Specifies	the length in 32-bit multiples of the data to be
	      retrieved.

       offset
	      Specifies	the offset in the specified property (in 32-bit
	      quantities) where	the data is to be retrieved.

       mode
	      One of XIPropModeAppend, XIPropModePrepend or XIPropModeReplace.

       num_items
	      Number of	items in data in the format specified.

       nitems_return
	      Returns the actual number	of 8-bit, 16-bit, or 32-bit items
	      stored in	data.

       property
	      Specifies	the property name.

       type
	      Specifies	the type of the	property.  The X server	does not
	      interpret	the type but simply passes it back to an application
	      that later calls XIGetProperty.

       type_return
	      Returns the atom identifier that defines the actual type of
	      the property.

DESCRIPTION
       The XIGetProperty 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. XIGetProperty
       sets the	return arguments as follows:

       o   If the specified property does not exist for	the specified device,
	   XIGetProperty returns None to actual_type_return and	the value zero
	   to actual_format_return and bytes_after_return. The nitems_return
	   argument is empty. In this case, the	delete argument	is ignored.

       o   If the specified property exists but	its type does not match	the
	   specified type, XIGetProperty returns the actual property type to
	   actual_type_return, the actual property format (never zero) to
	   actual_format_return, and the property length in bytes (even	if the
	   actual_format_return	is 16 or 32) to	bytes_after_return. It also
	   ignores the delete argument.	The nitems_return argument is empty.

       o   If the specified property exists and	either you assign
	   XIAnyPropertyType to	the req_type argument or the specified type
	   matches the actual property type, XIGetProperty returns the actual
	   property type to actual_type_return and the actual property format
	   (never zero)	to actual_format_return. It also returns a value to
	   bytes_after_return and nitems_return, by defining the following
	   values:

	       N = length of the stored	property in bytes
	       I = 4 * offset
	       T = N - I
	       L = MINIMUM(T, 4	* length)
	       A = N - (I + L)

       The returned value starts at byte index I in the	property (indexing
       from zero), and its length in bytes is L. If the	value for long_offset
       causes L	to be negative,	a BadValue error results. The value of
       bytes_after_return is A,	giving the number of trailing unread bytes in
       the stored property.

       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 a uint16_t array and should be cast to that type to obtain the ele-
       ments. If the returned format is	32, the	returned data is represented
       as a uint32_t array and should be cast to that type to obtain the
       elements.

       XIGetProperty always allocates one extra	byte in	prop_return (even if
       the property is zero length) and	sets it	to zero	so that	simple
       properties consisting of	characters do not have to be copied into yet
       another string before use.

       If delete is True and bytes_after_return	is zero, XIGetProperty deletes
       the property from the window and	generates an XIPropertyNotify event on
       the window.

       The function returns Success if it executes successfully. To free the
       resulting data, use XFree.

       XIGetProperty can generate BadAtom, BadValue, and BadWindow errors.

       The XIChangeProperty function alters the	property for the specified
       device and causes the X server to generate a XIPropertyNotify event for
       that device. XIChangeProperty performs the following:

       o   If mode is XIPropModeReplace, XIChangeProperty discards the
	   previous property value and stores the new data.

       o   If mode is XIPropModePrepend	or XIPropModeAppend, XIChangeProperty
	   inserts the specified data before the beginning of the existing
	   data	or onto	the end	of the existing	data, respectively. The	type
	   and format must match the existing property value, or a BadMatch
	   error results. If the property is undefined,	it is treated as
	   defined with	the correct type and format with zero-length data.

       If the specified	format is 8, the property data must be a char array.
       If the specified	format is 16, the property data	must be	a uint16_t
       array. If the specified format is 32, the property data must be a
       uint32_t	array.

       The lifetime of a property is not tied to the storing client.
       Properties remain until explicitly deleted, until the device is
       removed,	or until the server resets. The	maximum	size of	a property is
       server dependent	and can	vary dynamically depending on the amount of
       memory the server has available.	(If there is insufficient space, a
       BadAlloc	error results.)

       XIChangeProperty	can generate BadAlloc, BadAtom,	BadMatch, BadValue,
       and BadDevice errors.

       The XIDeleteProperty function deletes the specified property only if
       the property was	defined	on the specified device	and causes the X
       server to generate a XIPropertyNotify event for the device unless the
       property	does not exist.

       XIDeleteProperty	can generate BadAtom and BadDevice errors.

DIAGNOSTICS
       BadAlloc	The server failed to allocate the requested resource or	server
       memory.

       BadAtom A value for an Atom argument does not name a defined Atom.

       BadValue	Some numeric value falls outside the range of values accepted
       by the 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.

       BadDevice An invalid device was specified. The device does not exist.

       BadAtom An invalid property was specified. The property does not	exist.

BUGS
	   The protocol	headers	for XI 2.0 did not provide
	   XIAnyPropertyType, XIPropModeReplace, XIPropModePrepend or
	   XIPropModeAppend. Use AnyPropertyType, PropModeReplace,
	   PropModePrepend and PropModeAppend instead, respectively.

SEE ALSO
       XIListProperties(3)

				  03/09/2013		   XICHANGEPROPERTY(3)

NAME | SYNOPSIS | DESCRIPTION | DIAGNOSTICS | BUGS | SEE ALSO

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