<s>
In	O
computing	O
,	O
the	O
red	B-Application
zone	I-Application
is	O
a	O
fixed-size	O
area	O
in	O
a	O
function	O
's	O
stack	O
frame	O
below	O
(	O
for	O
a	O
push-down	O
stack	O
)	O
the	O
current	O
stack	O
pointer	O
that	O
is	O
reserved	O
and	O
safe	O
to	O
use	O
.	O
</s>
<s>
Whether	O
a	O
red	B-Application
zone	I-Application
is	O
present	O
depends	O
on	O
the	O
calling	O
convention	O
.	O
</s>
<s>
x86-64	B-Device
systems	O
that	O
use	O
the	O
System	O
V	O
AMD64	B-Device
ABI	O
(	O
including	O
Linux	B-Application
and	O
macOS	B-Application
)	O
use	O
a	O
128-byte	O
red	B-Application
zone	I-Application
that	O
begins	O
directly	O
under	O
the	O
current	O
value	O
of	O
the	O
stack	O
pointer	O
.	O
</s>
<s>
The	O
OpenRISC	B-Device
toolchain	B-General_Concept
assumes	O
a	O
128-byte	O
red	B-Application
zone	I-Application
.	O
</s>
<s>
Microsoft	O
Windows	O
does	O
not	O
have	O
the	O
concept	O
of	O
a	O
red	B-Application
zone	I-Application
on	O
x86	B-Operating_System
.	O
</s>
<s>
In	O
fact	O
,	O
the	O
ABI	O
explicitly	O
states	O
that	O
the	O
memory	O
beyond	O
the	O
stack	O
pointer	O
is	O
volatile	O
and	O
may	O
be	O
overwritten	O
by	O
debuggers	O
or	O
interrupt	B-General_Concept
handlers	I-General_Concept
.	O
</s>
<s>
However	O
,	O
Microsoft	O
Windows	O
has	O
a	O
red	B-Application
zone	I-Application
of	O
16	O
bytes	O
on	O
IA-64	B-General_Concept
,	O
8	O
bytes	O
on	O
AArch32	O
,	O
and	O
16	O
bytes	O
on	O
AArch64	B-Architecture
.	O
</s>
<s>
The	O
red	B-Application
zone	I-Application
is	O
safe	O
from	O
modification	O
by	O
interrupt/exception/signal	O
handlers	O
.	O
</s>
