<s>
FreeBASIC	B-Language
is	O
a	O
free	B-License
and	I-License
open	I-License
source	I-License
multiplatform	O
compiler	B-Language
and	O
programming	O
language	O
based	O
on	O
BASIC	O
licensed	O
under	O
the	O
GNU	B-License
GPL	I-License
for	O
Microsoft	B-Application
Windows	I-Application
,	O
protected-mode	O
MS-DOS	B-Application
(	O
DOS	B-Device
extender	I-Device
)	O
,	O
Linux	B-Application
,	O
FreeBSD	B-Operating_System
and	O
Xbox	B-Application
.	O
</s>
<s>
The	O
Xbox	B-Application
version	O
is	O
no	O
longer	O
maintained	O
.	O
</s>
<s>
According	O
to	O
its	O
official	O
website	O
,	O
FreeBASIC	B-Language
provides	O
syntax	O
compatibility	O
with	O
programs	O
originally	O
written	O
in	O
Microsoft	B-Language
QuickBASIC	I-Language
(	O
QB	O
)	O
.	O
</s>
<s>
Unlike	O
QuickBASIC	B-Language
,	O
however	O
,	O
FreeBASIC	B-Language
is	O
a	O
command	O
line	O
only	O
compiler	B-Language
,	O
unless	O
users	O
manually	O
install	O
an	O
external	O
integrated	B-Application
development	I-Application
environment	I-Application
(	O
IDE	O
)	O
of	O
their	O
choice	O
.	O
</s>
<s>
IDEs	O
specifically	O
made	O
for	O
FreeBASIC	B-Language
include	O
FBide	O
and	O
FbEdit	O
,	O
while	O
more	O
graphical	O
options	O
include	O
WinFBE	O
Suite	O
and	O
VisualFBEditor	O
.	O
</s>
<s>
On	O
its	O
backend	B-Architecture
,	O
FreeBASIC	B-Language
makes	O
use	O
of	O
GNU	B-Application
Binutils	I-Application
in	O
order	O
to	O
produce	O
console	O
and	O
graphical	B-Application
user	I-Application
interface	I-Application
applications	O
.	O
</s>
<s>
FreeBASIC	B-Language
supports	O
the	O
linking	O
and	O
creation	O
of	O
C	B-Language
static	O
and	O
dynamic	O
libraries	B-Library
and	O
has	O
limited	O
support	O
for	O
C++	B-Language
libraries	B-Library
.	O
</s>
<s>
As	O
a	O
result	O
,	O
code	O
compiled	B-Language
in	O
FreeBASIC	B-Language
can	O
be	O
reused	O
in	O
most	O
native	O
development	O
environments	O
.	O
</s>
<s>
C	B-Language
style	I-Language
preprocessing	I-Language
,	O
including	O
multiline	O
macros	O
,	O
conditional	O
compiling	B-Language
and	O
file	O
inclusion	O
,	O
is	O
supported	O
.	O
</s>
<s>
The	O
preprocessor	O
also	O
has	O
access	O
to	O
symbol	O
information	O
and	O
compiler	B-Language
settings	O
,	O
such	O
as	O
the	O
language	O
dialect	O
.	O
</s>
<s>
Initially	O
,	O
FreeBASIC	B-Language
emulated	O
Microsoft	B-Language
QuickBASIC	I-Language
syntax	O
as	O
closely	O
as	O
possible	O
.	O
</s>
<s>
As	O
a	O
result	O
,	O
FreeBASIC	B-Language
combines	O
several	O
language	O
dialects	O
for	O
maximum	O
level	O
of	O
compatibility	O
with	O
QuickBASIC	B-Language
and	O
full	O
access	O
to	O
modern	O
features	O
.	O
</s>
<s>
New	O
features	O
include	O
support	O
for	O
concepts	O
such	O
as	O
objects	O
,	O
operator	O
overloading	O
,	O
function	B-Language
overloading	I-Language
,	O
namespaces	O
and	O
others	O
.	O
</s>
<s>
Full	O
line	O
comments	O
are	O
made	O
with	O
an	O
apostrophe	B-Language
'	O
,	O
while	O
blocks	O
of	O
commented	O
code	O
begin	O
with	O
/	O
'	O
and	O
end	O
with	O
'	O
/	O
.	O
</s>
<s>
FreeBASIC	B-Language
is	O
not	O
case-sensitive	O
.	O
</s>
<s>
FreeBASIC	B-Language
provides	O
built-in	O
,	O
QuickBASIC	B-Language
compatible	O
graphics	O
support	O
through	O
FBgfx	O
,	O
which	O
is	O
automatically	O
included	O
into	O
programs	O
that	O
make	O
a	O
call	O
to	O
the	O
SCREEN	O
command	O
.	O
</s>
<s>
Its	O
backend	B-Architecture
defaults	O
to	O
OpenGL	B-Application
on	O
Linux	B-Application
and	O
DirectX	B-Application
on	O
Microsoft	B-Application
Windows	I-Application
.	O
</s>
<s>
Users	O
familiar	O
with	O
external	O
graphics	O
utilities	O
such	O
as	O
OpenGL	B-Application
or	O
the	O
Windows	O
API	O
can	O
use	O
them	O
without	O
interfering	O
with	O
the	O
built-in	O
graphics	O
library	O
.	O
</s>
<s>
As	O
FreeBASIC	B-Language
has	O
evolved	O
,	O
changes	O
have	O
been	O
made	O
that	O
required	O
breaking	O
older-styled	O
syntax	O
.	O
</s>
<s>
In	O
order	O
to	O
continue	O
supporting	O
programs	O
written	O
using	O
the	O
older	O
syntax	O
,	O
FreeBASIC	B-Language
now	O
supports	O
the	O
following	O
dialects	O
:	O
</s>
<s>
The	O
default	O
dialect	O
(	O
-lang	O
fb	O
as	O
a	O
command-line	O
argument	O
)	O
supports	O
all	O
new	O
compiler	B-Language
features	O
and	O
disallows	O
archaic	O
syntax	O
.	O
</s>
<s>
The	O
FB-lite	O
dialect	O
(	O
-lang	O
fblite	O
)	O
permits	O
use	O
of	O
most	O
new	O
,	O
non-object-oriented	O
features	O
in	O
addition	O
to	O
older-style	O
programming	O
.	O
</s>
<s>
Implicit	O
variables	O
,	O
suffixes	O
,	O
GOSUB	B-Device
/	O
RETURN	O
,	O
numeric	B-Application
labels	I-Application
and	O
other	O
features	O
are	O
allowed	O
in	O
this	O
dialect	O
.	O
</s>
<s>
The	O
QB	O
dialect	O
(	O
-lang	O
qb	O
)	O
attempts	O
to	O
replicate	O
QuickBASIC	B-Language
behavior	O
and	O
is	O
able	O
to	O
compile	B-Language
many	O
QuickBASIC	B-Language
programs	O
without	O
modification	O
.	O
</s>
<s>
program	B-Application
are	O
done	O
just	O
as	O
they	O
were	O
in	O
QuickBASIC	B-Language
.	O
</s>
<s>
FreeBASIC	B-Language
adds	O
to	O
this	O
with	O
support	O
for	O
object-oriented	B-Language
features	O
such	O
as	O
methods	B-Language
,	O
constructors	O
,	O
dynamic	O
memory	O
allocation	O
,	O
properties	B-Language
and	O
temporary	O
allocation	O
.	O
</s>
