int XGetWindowProperty (actual_type_return, actual_format_return,
nitems_return, bytes_after_return,
Display *display, Window w,
Atom property, long long_offset,
long 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)
Atom *XListProperties (Display *display, Window w,
int *num_prop_return)
XChangeProperty (Display *display, Window w, Atom property,
Atom type, int format, int mode,
unsigned char *data, int nelements)
XRotateWindowProperties (Display *display, Window w,
Atom properties[], int num_prop,
int npositions)
XDeleteProperty (Display *display, Window w, Atom property)
Returns the atom identifier that defines the actual type 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 whether the property
is deleted.
display
Specifies the connection to the X server.
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 XChangeProperty(3).
long_length
Specifies the length in 32-bit multiples of the data to be
retrieved.
long_offset
Specifies the offset in the specified property (in 32-bit
quantities) where the data is to be retrieved.
mode
Specifies the mode of the operation. You can pass
PropModeReplace, PropModePrepend, or PropModeAppend.
nelements
Specifies the number of elements of the specified data
format.
nitems_return
Returns the actual number of 8-bit, 16-bit, or 32-bit items
stored in the prop_return data.
num_prop
Specifies the length of the properties array.
num_prop_return
Returns the length of the properties array.
npositions
Specifies the rotation amount.
prop_return
Returns the data in the specified format.
property
Specifies the property name.
properties
Specifies the array of properties that are to be rotated.
req_type
Specifies the atom identifier associated with the property type
or AnyPropertyType .
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 XGetWindowProperty .
w
Specifies the window whose property you want to obtain, change,
rotate or delete.
The XGetWindowProperty(3) 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. XGetWindowProperty(3) sets the return
arguments as follows:
If the specified property does not exist for the specified
window, XGetWindowProperty(3) 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.
If the specified property exists but its type does not match
the specified type, XGetWindowProperty(3) 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.
If the specified property exists and either you assign
AnyPropertyType to the req_type argument or the specified
type matches the actual property type, XGetWindowProperty(3) 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 =
actual length of the stored property in bytes (even if the
format is 16 or 32)
I =
4 * long_offset
T =
N - I
L =
MINIMUM(T, 4 * long_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.
XGetWindowProperty(3) always allocates one extra
byte in prop_return (even if the property is zero length)
and sets it to ASCII null 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, XGetWindowProperty(3) deletes the property from
the window and generates a PropertyNotify event on the window.
The function returns Success if it executes successfully. To
free the resulting data, use XFree(3).
XGetWindowProperty(3) can generate BadAtom,
BadValue, and BadWindow errors.
The XListProperties(3) function returns a pointer to
an array of atom properties that are defined for the specified
window or returns NULL if no properties were found. To free the
memory allocated by this function, use XFree(3).
The XChangeProperty(3) function alters the property
for the specified window and causes the X server to generate a
PropertyNotify event on that window. XChangeProperty(3)
performs the following:
If mode is PropModeReplace, XChangeProperty(3)
discards the previous property value and stores the new data.
If mode is PropModePrepend or PropModeAppend, XChangeProperty(3) 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.
The lifetime of a property is not tied to the storing client.
Properties remain until explicitly deleted, until the window is
destroyed, or until the server resets. For a discussion of what
happens when the connection to the X server is closed, see section
2.6. 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.)
XChangeProperty(3) can generate BadAlloc,
BadAtom, BadMatch, BadValue, and BadWindow errors.
The XRotateWindowProperties(3) function allows you to
rotate properties on a window and causes the X server to generate
PropertyNotify events. If the property names in the properties
array are viewed as being numbered starting from zero and if there
are num_prop property names in the list, then the value
associated with property name I becomes the value associated with
property name (I + npositions) mod N for all I from zero to N - 1.
The effect is to rotate the states by npositions places around the
virtual ring of property names (right for positive npositions, left
for negative npositions). If npositions mod N is nonzero, the X
server generates a PropertyNotify event for each property in the
order that they are listed in the array. If an atom occurs more
than once in the list or no property with that name is defined for
the window, a BadMatch error results. If a BadAtom or BadMatch
error results, no properties are changed.
The XDeleteProperty(3) function deletes the specified
property only if the property was defined on the specified window
and causes the X server to generate a PropertyNotify event on the
window unless the property does not exist.
XDeleteProperty(3) can generate BadAtom and
BadWindow errors.
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.
BadWindow
A value for a Window argument does not name a defined
Window.