<s>
A	O
binary-safe	B-General_Concept
function	O
is	O
one	O
that	O
treats	O
its	O
input	O
as	O
a	O
raw	O
stream	O
of	O
bytes	O
and	O
ignores	O
every	O
textual	O
aspect	O
it	O
may	O
have	O
.	O
</s>
<s>
The	O
term	O
is	O
mainly	O
used	O
in	O
the	O
PHP	B-Application
programming	I-Application
language	I-Application
to	O
describe	O
expected	O
behaviour	O
when	O
passing	O
binary	O
data	O
into	O
functions	O
whose	O
main	O
responsibility	O
is	O
text	O
and	O
string	O
manipulating	O
,	O
and	O
is	O
used	O
widely	O
in	O
the	O
official	O
PHP	B-Application
documentation	O
.	O
</s>
<s>
While	O
all	O
textual	O
data	O
can	O
be	O
represented	O
in	O
binary-form	O
,	O
it	O
must	O
be	O
done	O
so	O
through	O
character	B-General_Concept
encoding	I-General_Concept
.	O
</s>
<s>
For	O
example	O
,	O
in	O
the	O
PHP	B-Application
programming	I-Application
language	I-Application
,	O
developers	O
have	O
to	O
use	O
fopen($filename, "rb" )	O
instead	O
of	O
fopen($filename, "r" )	O
to	O
read	O
the	O
file	O
as	O
a	O
binary	O
stream	O
instead	O
of	O
interpreting	O
the	O
textual	O
data	O
as	O
such	O
.	O
</s>
<s>
This	O
may	O
also	O
be	O
referred	O
to	O
as	O
reading	O
in	O
'	O
binary	B-General_Concept
safe	I-General_Concept
 '	O
mode	O
.	O
</s>
