<s>
Meta	O
Object	O
System	O
is	O
a	O
part	O
of	O
Qt	B-Language
framework	I-Language
core	O
provided	O
to	O
support	O
Qt	B-Language
extensions	O
to	O
C++	B-Language
like	O
signals/slots	B-Language
for	O
inter-object	O
communication	O
,	O
run-time	O
type	O
information	O
,	O
and	O
the	O
dynamic	O
property	O
system	O
.	O
</s>
<s>
The	O
Meta	O
object	O
system	O
consists	O
of	O
3	O
things	O
:	O
QObject	O
class	O
,	O
Q_OBJECT	O
macro	O
and	O
a	O
tool	O
called	O
moc	O
(	O
Meta-Object	O
Compiler	B-Language
)	O
.	O
</s>
<s>
QObject	O
is	O
the	O
base	O
class	O
for	O
all	O
Qt	B-Language
classes	O
,	O
Q_OBJECT	O
macro	O
is	O
used	O
to	O
enable	O
meta-object	O
features	O
in	O
classes	O
and	O
finally	O
moc	O
is	O
a	O
preprocessor	B-General_Concept
that	O
changes	O
Q_OBJECT	O
macro	O
instances	O
to	O
C++	B-Language
source	O
code	O
to	O
enable	O
meta	O
object	O
system	O
mechanism	O
in	O
the	O
class	O
in	O
which	O
it	O
is	O
used	O
.	O
</s>
<s>
In	O
Qt	B-Language
documentation	O
,	O
several	O
reasons	O
have	O
been	O
given	O
for	O
the	O
use	O
of	O
the	O
meta	O
object	O
system	O
,	O
including	O
benefits	O
of	O
code	B-Application
generation	I-Application
,	O
dynamism	O
of	O
GUIs	B-Application
,	O
automatic	O
binding	O
to	O
scripting	O
languages	O
,	O
not	O
adding	O
limitations	O
and	O
also	O
reasonable	O
performance	O
in	O
signal/slot	O
implementation	O
with	O
moc	O
.	O
</s>
<s>
There	O
are	O
some	O
efforts	O
to	O
make	O
Qt	B-Language
needless	O
of	O
a	O
preprocessor	B-General_Concept
.	O
</s>
<s>
These	O
efforts	O
include	O
re-implementing	O
Qt	B-Language
moc	O
using	O
libclang	O
.	O
</s>
