<s>
In	O
computer	B-General_Concept
science	I-General_Concept
,	O
an	O
anonymous	B-Operating_System
pipe	I-Operating_System
is	O
a	O
simplex	O
FIFO	B-Operating_System
communication	O
channel	O
that	O
may	O
be	O
used	O
for	O
one-way	O
interprocess	B-Operating_System
communication	I-Operating_System
(	O
IPC	O
)	O
.	O
</s>
<s>
An	O
implementation	O
is	O
often	O
integrated	O
into	O
the	O
operating	B-General_Concept
system	I-General_Concept
's	O
file	B-General_Concept
IO	I-General_Concept
subsystem	O
.	O
</s>
<s>
Typically	O
a	O
parent	O
program	O
opens	O
anonymous	B-Operating_System
pipes	I-Operating_System
,	O
and	O
creates	O
a	O
new	O
process	O
that	O
inherits	O
the	O
other	O
ends	O
of	O
the	O
pipes	B-Operating_System
,	O
or	O
creates	O
several	O
new	O
processes	O
and	O
arranges	O
them	O
in	O
a	O
pipeline	B-Operating_System
.	O
</s>
<s>
Full-duplex	O
(	O
two-way	O
)	O
communication	O
normally	O
requires	O
two	O
anonymous	B-Operating_System
pipes	I-Operating_System
.	O
</s>
<s>
Pipelines	B-Operating_System
are	O
supported	O
in	O
most	O
popular	O
operating	B-General_Concept
systems	I-General_Concept
,	O
from	O
Unix	B-Application
and	O
DOS	B-Device
onwards	O
,	O
and	O
are	O
created	O
using	O
the	O
"	O
|	O
"	O
character	O
in	O
many	O
shells	O
.	O
</s>
<s>
Pipelines	B-Operating_System
are	O
an	O
important	O
part	O
of	O
many	O
traditional	B-Application
Unix	I-Application
applications	O
and	O
support	O
for	O
them	O
is	O
well	O
integrated	O
into	O
most	O
Unix-like	B-Operating_System
operating	I-Operating_System
systems	I-Operating_System
.	O
</s>
<s>
Pipes	B-Operating_System
are	O
created	O
using	O
the	O
pipe	O
system	B-Operating_System
call	I-Operating_System
,	O
which	O
creates	O
a	O
new	O
pipe	O
and	O
returns	O
a	O
pair	O
of	O
file	B-Application
descriptors	I-Application
referring	O
to	O
the	O
read	O
and	O
write	O
ends	O
of	O
the	O
pipe	O
.	O
</s>
<s>
Many	O
traditional	B-Application
Unix	I-Application
programs	O
are	O
designed	O
as	O
filters	O
to	O
work	O
with	O
pipes	B-Operating_System
.	O
</s>
<s>
Like	O
many	O
other	O
device	O
IO	B-General_Concept
and	O
IPC	O
facilities	O
in	O
the	O
Windows	B-Library
API	I-Library
,	O
anonymous	B-Operating_System
pipes	I-Operating_System
are	O
created	O
and	O
configured	O
with	O
API	O
functions	O
that	O
are	O
specific	O
to	O
the	O
IO	B-General_Concept
facility	O
.	O
</s>
<s>
In	O
this	O
case	O
CreatePipe	O
is	O
used	O
to	O
create	O
an	O
anonymous	B-Operating_System
pipe	I-Operating_System
with	O
separate	O
handles	O
for	O
the	O
read	O
and	O
write	O
ends	O
of	O
the	O
pipe	O
.	O
</s>
<s>
Read	O
and	O
write	O
IO	B-General_Concept
operations	O
on	O
the	O
pipe	O
are	O
performed	O
with	O
the	O
standard	O
IO	B-General_Concept
facility	O
API	O
functions	O
ReadFile	O
and	O
WriteFile	O
.	O
</s>
<s>
On	O
Microsoft	B-Application
Windows	I-Application
,	O
reads	O
and	O
writes	O
to	O
anonymous	B-Operating_System
pipes	I-Operating_System
are	O
always	O
blocking	O
.	O
</s>
<s>
In	O
other	O
words	O
,	O
a	O
read	O
from	O
an	O
empty	O
pipe	O
will	O
cause	O
the	O
calling	O
thread	O
to	O
wait	O
until	O
at	O
least	O
one	O
byte	O
becomes	O
available	O
or	O
an	O
end-of-file	B-Language
is	O
received	O
as	O
a	O
result	O
of	O
the	O
write	O
handle	O
of	O
the	O
pipe	O
being	O
closed	O
.	O
</s>
<s>
New	O
processes	O
can	O
inherit	O
handles	O
to	O
anonymous	B-Operating_System
pipes	I-Operating_System
in	O
the	O
creation	O
process	O
.	O
</s>
