<s>
The	O
Apache	B-Language
Portable	I-Language
Runtime	I-Language
(	O
APR	O
)	O
is	O
a	O
supporting	O
library	B-Library
for	O
the	O
Apache	B-Application
web	I-Application
server	I-Application
.	O
</s>
<s>
It	O
provides	O
a	O
set	O
of	O
APIs	B-General_Concept
that	O
map	O
to	O
the	O
underlying	O
operating	O
system	O
(	O
OS	O
)	O
.	O
</s>
<s>
APR	O
originally	O
formed	O
a	O
part	O
of	O
Apache	B-Application
HTTP	I-Application
Server	I-Application
,	O
but	O
the	O
Apache	B-Application
Software	O
Foundation	O
spun	O
it	O
off	O
into	O
a	O
separate	O
project	O
.	O
</s>
<s>
Other	O
applications	O
can	O
use	O
it	O
to	O
achieve	O
platform	B-Operating_System
independence	I-Operating_System
.	O
</s>
<s>
The	O
range	O
of	O
platform-independent	B-Operating_System
functionality	O
provided	O
by	O
APR	O
includes	O
:	O
</s>
<s>
GLib	B-Language
–	O
provides	O
similar	O
functionality	O
.	O
</s>
<s>
It	O
supports	O
many	O
more	O
data	O
structures	O
and	O
OS-independent	O
functions	O
,	O
but	O
fewer	O
IPC-related	O
functions	O
.	O
</s>
<s>
(	O
GLib	B-Language
lacks	O
local	O
and	O
global	O
locking	B-Operating_System
and	O
shared-memory	B-Operating_System
management	O
.	O
)	O
</s>
<s>
Netscape	B-Application
Portable	I-Application
Runtime	I-Application
(	O
NSPR	B-Application
)	O
is	O
a	O
cross-platform	B-Operating_System
abstraction	O
library	B-Library
used	O
by	O
the	O
Mozilla	B-Operating_System
project	I-Operating_System
.	O
</s>
<s>
It	O
is	O
used	O
by	O
another	O
subproject	O
of	O
Mozilla	B-Application
application	I-Application
framework	I-Application
(	O
XPFE	B-Application
)	O
to	O
provide	O
cross-platform	B-Operating_System
graphical	B-Application
user	I-Application
interface	I-Application
(	O
GUI	B-Application
)	O
functionality	O
.	O
</s>
<s>
Adaptive	B-Language
Communication	I-Language
Environment	I-Language
(	O
ACE	O
)	O
is	O
an	O
object-oriented	O
library	B-Library
written	O
in	O
C++	O
similar	O
in	O
functionality	O
to	O
APR	O
.	O
</s>
<s>
is	O
a	O
cross-platform	B-Operating_System
C++	O
class	O
library	B-Library
for	O
systems	O
programming	O
,	O
with	O
much	O
of	O
the	O
same	O
functionality	O
as	O
APR	O
.	O
</s>
<s>
POCO	B-Language
is	O
a	O
modern	O
C++	O
framework	O
similar	O
in	O
concept	O
but	O
more	O
extensive	O
than	O
APR	O
.	O
</s>
<s>
WxWidgets	B-Language
is	O
an	O
object-oriented	O
cross-platform	B-Operating_System
GUI	B-Application
library	B-Library
that	O
also	O
provides	O
abstraction	O
classes	O
for	O
database	O
communication	O
,	O
IPC	B-Operating_System
and	O
networking	O
functionality	O
.	O
</s>
