<s>
For	O
developers	O
,	O
it	O
brought	O
OLE	B-Operating_System
Control	I-Operating_System
Extension	O
(	O
OCX	B-Operating_System
)	O
,	O
a	O
way	O
to	O
develop	O
and	O
use	O
custom	O
user	O
interface	O
elements	O
.	O
</s>
<s>
On	O
a	O
technical	O
level	O
,	O
an	O
OLE	B-Operating_System
object	I-Operating_System
is	O
any	O
object	O
that	O
implements	O
the	O
IOleObject	B-Operating_System
interface	O
,	O
possibly	O
along	O
with	O
a	O
wide	O
range	O
of	O
other	O
interfaces	O
,	O
depending	O
on	O
the	O
object	O
's	O
needs	O
.	O
</s>
<s>
OLE	O
allows	O
an	O
editing	O
application	B-Application
to	O
export	O
part	O
of	O
a	O
document	O
to	O
another	O
editing	O
application	B-Application
and	O
then	O
import	O
it	O
with	O
additional	O
content	O
.	O
</s>
<s>
For	O
example	O
,	O
a	O
desktop	O
publishing	O
system	O
might	O
send	O
some	O
text	O
to	O
a	O
word	B-General_Concept
processor	I-General_Concept
or	O
a	O
picture	O
to	O
a	O
bitmap	B-Application
editor	I-Application
using	O
OLE	O
.	O
</s>
<s>
The	O
main	O
benefit	O
of	O
OLE	O
is	O
to	O
add	O
different	O
kinds	O
of	O
data	O
to	O
a	O
document	O
from	O
different	O
applications	B-Application
,	O
like	O
a	O
text	O
editor	O
and	O
an	O
image	O
editor	O
.	O
</s>
<s>
OLE	O
is	O
also	O
used	O
for	O
transferring	O
data	O
between	O
different	O
applications	B-Application
using	O
drag	O
and	O
drop	O
and	O
clipboard	O
operations	O
.	O
</s>
<s>
OLE	O
1.0	O
,	O
released	O
in	O
1990	O
,	O
was	O
an	O
evolution	O
of	O
the	O
original	O
Dynamic	B-Operating_System
Data	I-Operating_System
Exchange	I-Operating_System
(	O
DDE	O
)	O
concept	O
that	O
Microsoft	O
developed	O
for	O
earlier	O
versions	O
of	O
Windows	B-Application
.	O
</s>
<s>
While	O
DDE	O
was	O
limited	O
to	O
transferring	O
limited	O
amounts	O
of	O
data	O
between	O
two	O
running	O
applications	B-Application
,	O
OLE	O
was	O
capable	O
of	O
maintaining	O
active	O
links	O
between	O
two	O
documents	O
or	O
even	O
embedding	O
one	O
type	O
of	O
document	O
within	O
another	O
.	O
</s>
<s>
OLE	B-Operating_System
servers	I-Operating_System
and	O
clients	O
communicate	O
with	O
system	O
libraries	O
using	O
virtual	B-Language
function	I-Language
tables	I-Language
,	O
or	O
VTBLs	B-Language
.	O
</s>
<s>
The	O
VTBL	B-Language
consists	O
of	O
a	O
structure	O
of	O
function	B-Language
pointers	I-Language
that	O
the	O
system	O
library	O
can	O
use	O
to	O
communicate	O
with	O
the	O
server	O
or	O
client	O
.	O
</s>
<s>
OLE	O
1.0	O
later	O
evolved	O
to	O
become	O
an	O
architecture	O
for	O
software	B-Architecture
components	I-Architecture
known	O
as	O
the	O
Component	B-Application
Object	I-Application
Model	I-Application
(	O
COM	O
)	O
,	O
and	O
later	O
DCOM	B-Operating_System
.	O
</s>
<s>
When	O
an	O
OLE	B-Operating_System
object	I-Operating_System
is	O
placed	O
on	O
the	O
clipboard	O
or	O
embedded	O
in	O
a	O
document	O
,	O
both	O
a	O
visual	O
representation	O
in	O
native	O
Windows	B-Application
formats	O
(	O
such	O
as	O
a	O
bitmap	O
or	O
metafile	O
)	O
is	O
stored	O
,	O
as	O
well	O
as	O
the	O
underlying	O
data	O
in	O
its	O
own	O
format	O
.	O
</s>
<s>
This	O
allows	O
applications	B-Application
to	O
display	O
the	O
object	O
without	O
loading	O
the	O
application	B-Application
used	O
to	O
create	O
the	O
object	O
,	O
while	O
also	O
allowing	O
the	O
object	O
to	O
be	O
edited	O
,	O
if	O
the	O
appropriate	O
application	B-Application
is	O
installed	O
.	O
</s>
<s>
The	O
Object	B-Operating_System
Packager	I-Operating_System
,	O
a	O
component	O
of	O
OLE	O
,	O
shipping	O
from	O
Windows	B-Application
3.1	I-Application
up	O
to	O
Windows	B-Application
XP	I-Application
allows	O
a	O
non-OLE	O
object	O
to	O
be	O
"	O
packaged	O
"	O
so	O
it	O
can	O
be	O
embedded	O
into	O
an	O
OLE	B-Application
client	I-Application
.	O
</s>
<s>
OLE	O
2.0	O
was	O
the	O
next	O
evolution	O
of	O
OLE	O
,	O
sharing	O
many	O
of	O
the	O
same	O
goals	O
as	O
version	O
1.0	O
,	O
but	O
was	O
re-implemented	O
on	O
top	O
of	O
the	O
COM	O
instead	O
of	O
using	O
VTBLs	B-Language
directly	O
.	O
</s>
<s>
New	O
features	O
were	O
OLE	B-Application
automation	I-Application
,	O
drag-and-drop	O
,	O
in-place	O
activation	O
and	O
structured	B-Library
storage	I-Library
.	O
</s>
<s>
Monikers	O
evolved	O
from	O
OLE	O
1	O
object	O
names	O
,	O
and	O
provided	O
a	O
hierarchical	O
object	O
and	O
resource	O
naming	O
system	O
similar	O
to	O
URLs	B-Protocol
or	I-Protocol
URIs	I-Protocol
,	O
which	O
were	O
independently	O
invented	O
.	O
</s>
<s>
Windows	B-Application
now	O
has	O
merged	O
the	O
two	O
technologies	O
supporting	O
a	O
URL	O
Moniker	O
type	O
,	O
and	O
a	O
Moniker	O
URL	O
scheme	O
.	O
</s>
<s>
OLE	O
custom	B-Library
controls	I-Library
were	O
introduced	O
in	O
1994	O
as	O
a	O
replacement	O
for	O
the	O
now	O
deprecated	O
Visual	B-Library
Basic	I-Library
Extension	I-Library
controls	O
.	O
</s>
<s>
In	O
particular	O
,	O
any	O
container	O
that	O
supported	O
OLE	O
2.0	O
could	O
already	O
embed	O
OLE	O
custom	B-Library
controls	I-Library
,	O
although	O
these	O
controls	O
cannot	O
react	O
to	O
events	O
unless	O
the	O
container	O
supports	O
this	O
.	O
</s>
<s>
OLE	O
custom	B-Library
controls	I-Library
are	O
usually	O
shipped	O
in	O
the	O
form	O
of	O
a	O
dynamic	O
link	O
library	O
with	O
the	O
.ocx	B-Operating_System
extension	O
.	O
</s>
<s>
In	O
1996	O
all	O
interfaces	O
for	O
controls	O
(	O
except	O
IUnknown	B-Application
)	O
were	O
made	O
optional	O
to	O
keep	O
the	O
file	O
size	O
of	O
controls	O
down	O
,	O
so	O
they	O
would	O
download	O
faster	O
;	O
these	O
were	O
then	O
called	O
ActiveX	B-Application
Controls	I-Application
.	O
</s>
<s>
OLE	B-Operating_System
objects	I-Operating_System
and	O
containers	O
are	O
implemented	O
on	O
top	O
of	O
the	O
Component	B-Application
Object	I-Application
Model	I-Application
;	O
they	O
are	O
objects	O
that	O
can	O
implement	O
interfaces	O
to	O
export	O
their	O
functionality	O
.	O
</s>
<s>
Only	O
the	O
IOleObject	B-Operating_System
interface	O
is	O
compulsory	O
,	O
but	O
other	O
interfaces	O
may	O
also	O
need	O
to	O
be	O
implemented	O
if	O
the	O
functionality	O
exported	O
by	O
those	O
interfaces	O
is	O
required	O
.	O
</s>
<s>
Interfaces	O
usually	O
implemented	O
by	O
the	O
OLE	B-Operating_System
object	I-Operating_System
are	O
usually	O
called	O
on	O
by	O
the	O
OLE	B-Operating_System
container	I-Operating_System
,	O
and	O
vice	O
versa	O
.	O
</s>
<s>
All	O
non-indented	O
interfaces	O
derive	O
from	O
IUnknown	B-Application
.	O
</s>
<s>
Allows	O
the	O
caller	O
to	O
inform	O
the	O
OLE	B-Operating_System
object	I-Operating_System
of	O
its	O
site	O
.	O
</s>
<s>
This	O
allows	O
an	O
embedded	O
object	O
to	O
store	O
its	O
visual	O
representation	O
,	O
thus	O
enabling	O
it	O
to	O
be	O
displayed	O
later	O
without	O
needing	O
to	O
start	O
the	O
application	B-Application
that	O
was	O
used	O
to	O
create	O
the	O
object	O
.	O
</s>
<s>
Allows	O
the	O
OLE	B-Operating_System
object	I-Operating_System
to	O
support	O
multiple	O
views	O
of	O
its	O
data	O
,	O
as	O
well	O
as	O
a	O
few	O
related	O
functions	O
.	O
</s>
<s>
For	O
example	O
,	O
if	O
the	O
mouse	O
is	O
moved	O
over	O
a	O
window	O
,	O
Windows	B-Application
places	O
a	O
mouse	O
move	O
message	O
along	O
with	O
the	O
mouse	O
coordinates	O
in	O
the	O
message	O
queue	O
of	O
the	O
window	O
.	O
</s>
<s>
Arguably	O
the	O
most	O
important	O
interface	O
for	O
an	O
OLE	B-Operating_System
object	I-Operating_System
.	O
</s>
<s>
Additionally	O
allows	O
the	O
implementer	O
to	O
receive	O
notifications	O
when	O
the	O
link	O
source	O
of	O
the	O
OLE	B-Operating_System
object	I-Operating_System
changes	O
.	O
</s>
<s>
Additionally	O
allows	O
the	O
implementer	O
to	O
receive	O
notifications	O
when	O
the	O
view	O
status	O
of	O
the	O
OLE	B-Operating_System
object	I-Operating_System
changes	O
.	O
</s>
<s>
The	O
methods	O
of	O
IOleObject	B-Operating_System
that	O
pertain	O
to	O
notifications	O
can	O
be	O
implemented	O
by	O
calling	O
the	O
methods	O
of	O
this	O
interface	O
.	O
</s>
<s>
Can	O
be	O
implemented	O
by	O
objects	O
(	O
OLE	B-Operating_System
objects	I-Operating_System
,	O
OLE	B-Operating_System
containers	I-Operating_System
,	O
and	O
other	O
objects	O
)	O
that	O
wish	O
to	O
support	O
certain	O
standard	O
commands	O
.	O
</s>
<s>
Currently	O
58	O
standard	O
commands	O
have	O
been	O
defined	O
,	O
and	O
they	O
include	O
commands	O
commonly	O
used	O
by	O
office	O
software	O
,	O
web	O
browsers	O
and	O
similar	O
applications	B-Application
.	O
</s>
<s>
OpenDoc	B-Application
technology	O
tried	O
to	O
compete	O
with	O
OLE	O
.	O
</s>
<s>
Some	O
of	O
Microsoft	O
's	O
competitors	O
considered	O
OpenDoc	B-Application
to	O
be	O
more	O
robust	O
and	O
easier	O
to	O
use	O
;	O
however	O
,	O
OpenDoc	B-Application
does	O
have	O
some	O
known	O
problems	O
.	O
</s>
<s>
OpenDoc	B-Application
allowed	O
users	O
to	O
view	O
and	O
edit	O
information	O
across	O
applications	B-Application
,	O
directly	O
in	O
competition	O
with	O
Microsoft	O
's	O
proprietary	O
OLE	O
standard	O
.	O
</s>
<s>
In	O
1993	O
some	O
Microsoft	O
competitors	O
established	O
a	O
consortium	O
called	O
the	O
Component	O
Integration	O
Laboratories	O
(	O
"	O
CIL	O
"	O
)	O
to	O
develop	O
OpenDoc	B-Application
as	O
an	O
open	O
standard	O
for	O
cross-platform	O
linking	O
and	O
embedding	O
.	O
</s>
<s>
Microsoft	O
required	O
OLE	O
compatibility	O
as	O
a	O
condition	O
of	O
Microsoft	O
's	O
certification	O
of	O
an	O
application	B-Application
's	O
compatibility	O
with	O
Windows	B-Application
95	I-Application
.	O
</s>
<s>
Microsoft	O
initially	O
announced	O
that	O
applications	B-Application
using	O
OpenDoc	B-Application
would	O
be	O
deemed	O
compatible	O
with	O
OLE	O
,	O
and	O
would	O
receive	O
certification	O
for	O
Windows	B-Application
95	I-Application
.	O
</s>
<s>
Microsoft	O
later	O
reversed	O
the	O
decision	O
and	O
said	O
that	O
applications	B-Application
using	O
OpenDoc	B-Application
might	O
not	O
receive	O
certification	O
at	O
all	O
.	O
</s>
<s>
Microsoft	O
withheld	O
specifications	O
and	O
debugged	O
versions	O
of	O
OLE	O
until	O
after	O
it	O
had	O
released	O
its	O
competing	O
applications	B-Application
.	O
</s>
<s>
Use	O
of	O
OLE	B-Operating_System
objects	I-Operating_System
limits	O
interoperability	O
,	O
because	O
these	O
objects	O
are	O
not	O
widely	O
supported	O
in	O
programs	O
for	O
viewing	O
or	O
editing	O
files	O
outside	O
of	O
Microsoft	B-Application
Windows	I-Application
(	O
e.g.	O
,	O
embedding	O
of	O
other	O
files	O
inside	O
the	O
file	O
,	O
such	O
as	O
tables	O
or	O
charts	O
from	O
a	O
spreadsheet	O
application	B-Application
in	O
a	O
text	O
document	O
or	O
presentation	O
file	O
)	O
.	O
</s>
<s>
If	O
software	O
that	O
understands	O
an	O
OLE	B-Operating_System
object	I-Operating_System
is	O
not	O
available	O
,	O
the	O
object	O
is	O
usually	O
replaced	O
by	O
a	O
picture	O
(	O
bitmap	O
representation	O
of	O
the	O
object	O
)	O
or	O
not	O
displayed	O
at	O
all	O
.	O
</s>
