<s>
Asynchronous	B-Device
procedure	I-Device
call	I-Device
is	O
a	O
unit	O
of	O
work	O
in	O
a	O
computer	O
.	O
</s>
<s>
So	O
life	O
cycle	O
of	O
an	O
asynchronous	B-Device
procedure	I-Device
call	I-Device
consists	O
of	O
2	O
stages	O
:	O
passive	O
stage	O
,	O
when	O
it	O
passively	O
waits	O
for	O
input	O
data	O
,	O
and	O
active	O
state	O
,	O
when	O
that	O
data	O
is	O
calculated	O
in	O
the	O
same	O
way	O
as	O
at	O
usual	O
procedure	O
call	O
.	O
</s>
<s>
The	O
object	O
of	O
the	O
asynchronous	B-Device
procedure	I-Device
call	I-Device
can	O
be	O
reused	O
for	O
subsequent	O
procedure	O
calls	O
with	O
new	O
data	O
,	O
received	O
later	O
.	O
</s>
<s>
Programming	O
using	O
Actors	O
is	O
described	O
in	O
Actor	B-Application
model	I-Application
and	O
Dataflow	B-Application
programming	I-Application
.	O
</s>
<s>
The	O
difference	O
is	O
that	O
Actor	O
in	O
the	O
Actor	B-Application
model	I-Application
has	O
exactly	O
two	O
ports	O
:	O
one	O
port	O
to	O
receive	O
input	O
data	O
,	O
and	O
another	O
(	O
hidden	O
)	O
port	O
to	O
provide	O
serial	O
handling	O
of	O
input	O
messages	O
,	O
while	O
Actor	O
in	O
Dataflow	B-Application
programming	I-Application
can	O
have	O
many	O
,	O
and	O
goes	O
to	O
execution	O
service	O
when	O
all	O
inputs	O
contain	O
data	O
or	O
permissions	O
.	O
</s>
<s>
In	O
Windows	O
,	O
an	O
asynchronous	B-Device
procedure	I-Device
call	I-Device
(	O
abbreviated	O
APC	O
)	O
is	O
a	O
function	O
that	O
executes	O
asynchronously	O
in	O
the	O
context	O
of	O
a	O
specific	O
thread	O
.	O
</s>
