<s>
Qt	B-Language
(	O
pronounced	O
"	O
cute	O
"	O
)	O
is	O
a	O
free	O
as	O
in	O
"	O
freedom	O
"	O
cross-platform	B-Operating_System
software	I-Operating_System
for	O
creating	O
graphical	B-Application
user	I-Application
interfaces	I-Application
as	O
well	O
as	O
cross-platform	B-Operating_System
applications	B-Application
that	O
run	O
on	O
various	O
software	O
and	O
hardware	O
platforms	O
such	O
as	O
Linux	B-Application
,	O
Windows	O
,	O
macOS	B-Application
,	O
Android	B-Application
or	O
embedded	B-Architecture
systems	I-Architecture
with	O
little	O
or	O
no	O
change	O
in	O
the	O
underlying	O
codebase	O
while	O
still	O
being	O
a	O
native	O
application	O
with	O
native	O
capabilities	O
and	O
speed	O
.	O
</s>
<s>
Qt	B-Language
is	O
currently	O
being	O
developed	O
by	O
The	O
Qt	B-Language
Company	O
,	O
a	O
publicly	O
listed	O
company	O
,	O
and	O
the	O
Qt	B-Language
Project	I-Language
under	O
open-source	B-License
governance	O
,	O
involving	O
individual	O
developers	O
and	O
organizations	O
working	O
to	O
advance	O
Qt	B-Language
.	O
</s>
<s>
Qt	B-Language
is	O
available	O
under	O
both	O
commercial	O
licenses	O
and	O
open-source	B-License
GPL	B-License
2.0	O
,	O
GPL	B-License
3.0	O
,	O
and	O
LGPL	B-Application
3.0	I-Application
licenses	O
.	O
</s>
<s>
Qt	B-Language
is	O
used	O
for	O
developing	O
graphical	B-Application
user	I-Application
interfaces	I-Application
(	O
GUIs	B-Application
)	O
and	O
multi-platform	B-Operating_System
applications	B-Application
that	O
run	O
on	O
all	O
major	O
desktop	B-Device
platforms	O
and	O
most	O
mobile	O
or	O
embedded	B-Application
platforms	O
.	O
</s>
<s>
Most	O
GUI	B-Application
programs	O
created	O
with	O
Qt	B-Language
have	O
a	O
native-looking	O
interface	O
,	O
in	O
which	O
case	O
Qt	B-Language
is	O
classified	O
as	O
a	O
widget	B-Library
toolkit	I-Library
.	O
</s>
<s>
Non-GUI	O
programs	O
can	O
also	O
be	O
developed	O
,	O
such	O
as	O
command-line	B-Application
tools	I-Application
and	O
consoles	O
for	O
servers	O
.	O
</s>
<s>
An	O
example	O
of	O
such	O
a	O
non-GUI	O
program	O
using	O
Qt	B-Language
is	O
the	O
Cutelyst	O
web	B-Application
framework	I-Application
.	O
</s>
<s>
Qt	B-Language
supports	O
various	O
compilers	O
,	O
including	O
the	O
GCC	B-Application
C++	B-Language
compiler	O
,	O
the	O
Visual	B-Application
Studio	I-Application
suite	O
,	O
PHP	B-Application
via	O
an	O
extension	O
for	O
PHP5	O
,	O
and	O
has	O
extensive	O
internationalization	B-General_Concept
support	O
.	O
</s>
<s>
Qt	B-Language
also	O
provides	O
Qt	B-Language
Quick	I-Language
,	O
that	O
includes	O
a	O
declarative	B-Language
scripting	B-Language
language	I-Language
called	O
QML	B-Language
that	O
allows	O
using	O
JavaScript	B-Language
to	O
provide	O
the	O
logic	O
.	O
</s>
<s>
With	O
Qt	B-Language
Quick	I-Language
,	O
rapid	O
application	O
development	O
for	O
mobile	O
devices	O
became	O
possible	O
,	O
while	O
logic	O
can	O
still	O
be	O
written	O
with	O
native	O
code	O
as	O
well	O
to	O
achieve	O
the	O
best	O
possible	O
performance	O
.	O
</s>
<s>
Other	O
features	O
include	O
SQL	B-Language
database	I-Language
access	O
,	O
XML	B-Protocol
parsing	O
,	O
JSON	B-General_Concept
parsing	O
,	O
thread	B-Operating_System
management	I-Operating_System
and	O
network	O
support	O
.	O
</s>
<s>
The	O
latest	O
version	O
of	O
the	O
Qt	B-Language
Framework	I-Language
is	O
Qt	B-Language
6.5	O
LTS	O
which	O
was	O
released	O
on	O
April	O
3rd	O
,	O
2023	O
.	O
</s>
<s>
In	O
addition	O
the	O
KDE	B-Application
project	O
provides	O
unofficial	O
support	O
for	O
,	O
at	O
least	O
,	O
Qt	B-Language
5.15	O
,	O
i.e.	O
</s>
<s>
In	O
2017	O
,	O
the	O
Qt	B-Language
Company	O
estimated	O
a	O
community	O
of	O
about	O
1	O
million	O
developers	O
worldwide	O
in	O
over	O
70	O
industries	O
.	O
</s>
<s>
Graphical	O
user-interfaces	O
and	O
desktop	B-Device
environments	O
that	O
utilize	O
Qt/QML	O
as	O
widget	B-Library
toolkit	I-Library
:	O
</s>
<s>
SDDM	B-Language
,	O
a	O
display	B-Device
manager	I-Device
that	O
is	O
X11	B-Operating_System
and	O
Wayland	B-Language
compatible	O
written	O
in	O
QML	B-Language
.	O
</s>
<s>
(	O
This	O
is	O
a	O
display	B-Device
manager	I-Device
and	O
not	O
a	O
desktop	B-Device
environment	O
.	O
)	O
</s>
<s>
Blackberry	B-Application
10	I-Application
,	O
a	O
touchscreen-based	O
mobile	O
OS	O
by	O
Blackberry	O
Ltd	O
.	O
</s>
<s>
Many	O
notable	O
open-source	B-License
or	O
proprietary	B-Application
cross-platform	B-Operating_System
software	I-Operating_System
are	O
using	O
Qt	B-Language
or	O
QML	B-Language
:	O
</s>
<s>
010	B-Operating_System
Editor	I-Operating_System
,	O
a	O
commercial	O
hex	O
editor	O
and	O
text	O
editor	O
for	O
Microsoft	B-Application
Windows	I-Application
,	O
Linux	B-Application
and	O
macOS	B-Application
.	O
</s>
<s>
AMD	O
's	O
Radeon	B-Application
Software	I-Application
Crimson	O
Edition	O
driver	O
tool	O
application	O
.	O
</s>
<s>
Audacious	B-Language
,	O
a	O
music	O
player	O
for	O
Linux	B-Application
,	O
Microsoft	B-Application
Windows	I-Application
,	O
and	O
other	O
Unix-like	B-Operating_System
operating	I-Operating_System
systems	I-Operating_System
.	O
</s>
<s>
Bitcoin	B-Language
Core	I-Language
,	O
the	O
reference	O
bitcoin	O
implementation	O
.	O
</s>
<s>
Most	O
bitcoin	O
forks	O
also	O
provide	O
the	O
reference	O
GUI	B-Application
.	O
</s>
<s>
Mathematica	B-Language
,	O
a	O
mathematical	O
symbolic	O
computation	O
program	O
,	O
sometimes	O
termed	O
a	O
computer	O
algebra	O
system	O
or	O
program	O
,	O
used	O
in	O
many	O
scientific	O
,	O
engineering	O
,	O
mathematical	O
,	O
and	O
computing	O
fields	O
.	O
</s>
<s>
Monero	B-Protocol
,	O
a	O
privacy-focused	O
cryptocurrency	O
,	O
implements	O
its	O
official	O
desktop	B-Device
wallet	B-Protocol
software	I-Protocol
using	O
Qt	B-Language
.	O
</s>
<s>
Qt	B-Language
is	O
built	O
on	O
these	O
key	O
concepts	O
:	O
</s>
<s>
Complete	O
abstraction	O
of	O
the	O
GUI	B-Application
When	O
first	O
released	O
,	O
Qt	B-Language
used	O
its	O
own	O
paint	O
engine	O
and	O
controls	O
,	O
emulating	O
the	O
look	O
of	O
the	O
different	O
platforms	O
it	O
runs	O
on	O
when	O
it	O
drew	O
its	O
widgets	O
.	O
</s>
<s>
This	O
made	O
the	O
porting	O
work	O
easier	O
because	O
very	O
few	O
classes	O
in	O
Qt	B-Language
really	O
depended	O
on	O
the	O
target	O
platform	O
;	O
however	O
,	O
this	O
occasionally	O
led	O
to	O
slight	O
discrepancies	O
where	O
that	O
emulation	O
was	O
imperfect	O
.	O
</s>
<s>
Recent	O
versions	O
of	O
Qt	B-Language
use	O
the	O
native	O
style	O
APIs	O
of	O
the	O
different	O
platforms	O
,	O
on	O
platforms	O
that	O
have	O
a	O
native	O
widget	B-Library
set	I-Library
,	O
to	O
query	O
metrics	O
and	O
draw	O
most	O
controls	O
,	O
and	O
do	O
not	O
suffer	O
from	O
such	O
issues	O
as	O
often	O
.	O
</s>
<s>
On	O
some	O
platforms	O
(	O
such	O
as	O
MeeGo	B-Operating_System
and	O
KDE	B-Application
)	O
Qt	B-Language
is	O
the	O
native	O
API	O
.	O
</s>
<s>
Some	O
other	O
portable	O
graphical	O
toolkits	O
have	O
made	O
different	O
design	O
decisions	O
;	O
for	O
example	O
,	O
wxWidgets	B-Language
uses	O
the	O
toolkits	O
of	O
the	O
target	O
platform	O
for	O
its	O
implementations	O
.	O
</s>
<s>
Signals	B-Language
and	I-Language
slots	I-Language
A	O
language	O
construct	O
introduced	O
in	O
Qt	B-Language
for	O
communication	O
between	O
objects	O
which	O
makes	O
it	O
easy	O
to	O
implement	O
the	O
observer	B-Language
pattern	I-Language
while	O
avoiding	O
boilerplate	O
code	O
.	O
</s>
<s>
The	O
concept	O
is	O
that	O
GUI	B-Application
widgets	O
can	O
send	O
signals	O
containing	O
event	O
information	O
which	O
can	O
be	O
received	O
by	O
other	O
controls	O
using	O
special	O
functions	O
known	O
as	O
slots	O
.	O
</s>
<s>
Metaobject	B-Language
compiler	O
The	O
metaobject	B-Language
compiler	O
,	O
termed	O
moc	O
,	O
is	O
a	O
tool	O
that	O
is	O
run	O
on	O
the	O
sources	O
of	O
a	O
Qt	B-Language
program	O
.	O
</s>
<s>
It	O
interprets	O
certain	O
macros	O
from	O
the	O
C++	B-Language
code	I-Language
as	O
annotations	O
,	O
and	O
uses	O
them	O
to	O
generate	B-Application
added	I-Application
C++	I-Application
code	I-Application
with	O
meta	O
information	O
about	O
the	O
classes	O
used	O
in	O
the	O
program	O
.	O
</s>
<s>
This	O
meta	O
information	O
is	O
used	O
by	O
Qt	B-Language
to	O
provide	O
programming	O
features	O
not	O
available	O
natively	O
in	O
C++	B-Language
:	O
signals	B-Language
and	I-Language
slots	I-Language
,	O
introspection	B-Application
and	O
asynchronous	O
function	O
calls	O
.	O
</s>
<s>
Language	O
bindingsQt	O
can	O
be	O
used	O
in	O
several	O
programming	O
languages	O
other	O
than	O
C++	B-Language
,	O
such	O
as	O
Python	O
,	O
Javascript	B-Language
,	O
C#	O
and	O
Rust	O
via	O
language	B-Application
bindings	I-Application
;	O
many	O
languages	O
have	O
bindings	B-Language
for	I-Language
Qt	I-Language
5	I-Language
and	O
bindings	B-Language
for	I-Language
Qt	I-Language
4	I-Language
.	O
</s>
<s>
Starting	O
with	O
Qt	B-Language
4.0	O
the	O
framework	O
was	O
split	O
into	O
individual	O
modules	O
.	O
</s>
<s>
With	O
Qt	B-Language
5.0	O
the	O
architecture	O
was	O
modularized	O
even	O
further	O
.	O
</s>
<s>
Qt	B-Language
is	O
now	O
split	O
into	O
essential	O
and	O
add-on	O
modules	O
.	O
</s>
<s>
ModuleDescription	O
Qt	B-Language
CoreThe	O
only	O
required	O
Qt	B-Language
module	O
,	O
containing	O
classes	O
used	O
by	O
other	O
modules	O
,	O
including	O
the	O
meta-object	B-Language
system	I-Language
,	O
concurrency	O
and	O
threading	O
,	O
containers	O
,	O
event	O
system	O
,	O
plugins	O
and	O
I/O	O
facilities.Qt	O
GUIThe	O
central	O
GUI	B-Application
module	O
.	O
</s>
<s>
In	O
Qt	B-Language
5	O
this	O
module	O
now	O
depends	O
on	O
OpenGL	B-Application
,	O
but	O
no	O
longer	O
contains	O
any	O
widget	O
classes.Qt	O
WidgetsContains	O
classes	O
for	O
classic	O
widget	O
based	O
GUI	B-Application
applications	B-Application
and	O
the	O
QSceneGraph	O
classes	O
.	O
</s>
<s>
Was	O
split	O
off	O
from	O
QtGui	O
in	O
Qt	B-Language
5.Qt	O
QMLModule	O
for	O
QML	B-Language
and	O
JavaScript	O
languages.Qt	O
QuickThe	O
module	O
for	O
GUI	B-Application
application	O
written	O
using	O
QML2.Qt	O
Quick	O
ControlsWidget	O
like	O
controls	O
for	O
Qt	B-Language
Quick	I-Language
intended	O
mainly	O
for	O
desktop	O
applications.Qt	O
Quick	O
LayoutsLayouts	O
for	O
arranging	O
items	O
in	O
Qt	B-Language
Quick.Qt	O
NetworkNetwork	O
abstraction	O
layer	O
.	O
</s>
<s>
Complete	O
with	O
support	O
for	O
TCP	B-Protocol
,	O
UDP	B-Protocol
,	O
HTTP	B-Protocol
,	O
TLS	B-Protocol
,	O
SSL	B-Protocol
(	O
in	O
Qt	B-Language
4	O
)	O
and	O
SPDY	B-Protocol
(	O
since	O
Qt	B-Language
5.3	O
)	O
.Qt	O
MultimediaClasses	O
for	O
audio	O
,	O
video	O
,	O
radio	O
and	O
camera	O
functionality.Qt	O
Multimedia	O
WidgetsThe	O
widgets	O
from	O
Qt	B-Language
Multimedia.Qt	O
SQLContains	O
classes	O
for	O
database	O
integration	O
using	O
SQL.Qt	O
WebEngineA	O
new	O
set	O
of	O
Qt	B-Language
Widget	O
and	O
QML	B-Language
webview	O
APIs	O
based	O
on	O
Chromium.Qt	O
TestClasses	O
for	O
unit	O
testing	O
Qt	B-Language
applications	B-Application
and	O
libraries	O
.	O
</s>
<s>
ModuleDescriptionActive	O
QtClasses	O
for	O
applications	B-Application
which	O
use	O
ActiveX.Qt	O
ChartsProvides	O
functionality	O
and	O
widgets	O
to	O
plot	O
charts	O
of	O
many	O
kindsQt	O
BluetoothClasses	O
accessing	O
Bluetooth	B-Protocol
hardware.Qt	O
D-BusClasses	O
for	O
IPC	O
using	O
the	O
D-Bus	B-Language
protocol.Qt	O
NFCClasses	O
accessing	O
NFC	O
hardware	O
.	O
</s>
<s>
Only	O
officially	O
supported	O
on	O
BlackBerry	O
hardware	O
so	O
far	O
(	O
or	O
N9	O
in	O
the	O
MeeGo	B-Operating_System
port	O
)	O
.Qt	O
OpenGLLegacy	O
module	O
containing	O
the	O
OpenGL	B-Application
classes	O
from	O
Qt	B-Language
4	O
.	O
</s>
<s>
In	O
Qt	B-Language
5	O
the	O
similar	O
functionality	O
in	O
Qt	B-Language
GUI	B-Application
is	O
recommended.Qt	O
LocationClasses	O
for	O
accessing	O
GPS	O
and	O
other	O
location	O
services	O
and	O
for	O
mapping	O
and	O
navigation	O
.	O
</s>
<s>
Split	O
off	O
from	O
the	O
Qt	B-Language
4	O
Mobility	O
module	O
of	O
Qt	B-Language
Location	O
.	O
</s>
<s>
Supported	O
on	O
Android	B-Application
,	O
BlackBerry	O
,	O
iOS	B-Application
,	O
Linux	B-Application
(	O
using	O
GeoClue	O
)	O
,	O
Windows	O
and	O
Sailfish	O
OS.Qt	O
Quick	O
3DClasses	O
for	O
rendering	O
3D	O
models	O
,	O
video	O
games	O
,	O
simulations	O
and	O
3D	B-General_Concept
user	I-General_Concept
interfaces	I-General_Concept
,	O
with	O
a	O
Qt	B-Language
QML	B-Language
API	O
,	O
into	O
a	O
mixed	O
2D	O
and	O
3D	O
scene	O
graph.Qt	O
ScriptLegacy	O
module	O
for	O
scripting	O
Qt	B-Language
application	O
using	O
ECMAScript/JavaScript	O
.	O
</s>
<s>
In	O
Qt	B-Language
5	O
,	O
using	O
similar	O
classes	O
in	O
Qt	B-Language
QML	B-Language
is	O
recommended.Qt	O
SensorsClasses	O
for	O
accessing	O
various	O
mobile	O
hardware	O
sensors	O
.	O
</s>
<s>
Used	O
to	O
be	O
part	O
of	O
Qt	B-Language
Mobile	O
in	O
Qt	B-Language
4	O
.	O
</s>
<s>
Supported	O
on	O
Android	B-Application
,	O
BlackBerry	O
,	O
iOS	B-Application
,	O
WinRT	O
,	O
Mer	O
and	O
Linux.Qt	O
Serial	O
PortClasses	O
for	O
access	O
to	O
hardware	O
and	O
virtual	O
serial	O
ports	O
.	O
</s>
<s>
Supported	O
on	O
Windows	O
,	O
Linux	B-Application
and	O
macOS.Qt	O
WebChannelProvides	O
access	O
to	O
Qt	B-Language
objects	O
to	O
HTML/Js	O
over	O
WebSockets.Qt	O
WebKitQt	O
's	O
WebKit	B-Language
implementation	O
and	O
API.Qt	O
WebKit	B-Language
WidgetsThe	O
widget	O
API	O
for	O
Qt	B-Language
WebKitQt	O
WebSocketsProvides	O
a	O
WebSocket	B-Protocol
implementation.Qt	O
XMLLegacy	O
module	O
containing	O
classes	O
for	O
SAX	B-Application
and	O
DOM	B-General_Concept
style	O
XML	B-Protocol
APIs	O
.	O
</s>
<s>
Replaced	O
with	O
QXmlStreamReader	O
and	O
QXmlStreamWriter	O
classes	O
in	O
Qt	B-Language
Core.Qt	O
XML	B-Protocol
PatternsSupport	O
for	O
XPath	B-Language
,	O
XQuery	B-Language
,	O
XSLT	B-Application
and	O
XML	B-Protocol
Schema	O
validation	O
.	O
</s>
<s>
There	O
are	O
four	O
editions	O
of	O
Qt	B-Language
available	O
:	O
Community	O
,	O
Indie	O
Mobile	O
,	O
Professional	O
and	O
Enterprise	O
.	O
</s>
<s>
The	O
Community	O
version	O
is	O
under	O
the	O
open	B-License
source	I-License
licenses	O
,	O
while	O
the	O
Indie	O
Mobile	O
,	O
Professional	O
and	O
Enterprise	O
versions	O
,	O
which	O
contain	O
additional	O
functionality	O
and	O
libraries	O
,	O
e.g.	O
</s>
<s>
Enterprise	O
Controls	O
are	O
commercially	O
sold	O
by	O
The	O
Qt	B-Language
Company	O
.	O
</s>
<s>
Qt	B-Language
works	O
on	O
many	O
different	O
platforms	O
;	O
the	O
following	O
are	O
officially	O
supported	O
:	O
</s>
<s>
Platform	O
Description	O
Linux/UnixX11	O
Qt	B-Language
for	O
X	B-Operating_System
Window	I-Operating_System
System	I-Operating_System
(	O
Linux	B-Application
)	O
;	O
FreeBSD	B-Operating_System
,	O
NetBSD	B-Device
,	O
OpenBSD	B-Operating_System
,	O
and	O
DragonFly	B-Application
BSD	I-Application
have	O
community	O
support.Wayland	O
Qt	B-Language
applications	B-Application
can	O
switch	O
between	O
graphical	O
backends	O
like	O
X	B-Operating_System
and	O
Wayland	B-Language
at	O
load	B-Operating_System
time	I-Operating_System
with	O
the	O
-platform	O
command	B-Application
line	I-Application
option	O
.	O
</s>
<s>
This	O
allows	O
a	O
seamless	O
transition	O
of	O
Qt	B-Language
applications	B-Application
from	O
X11	B-Operating_System
to	O
Wayland	B-Language
.	O
</s>
<s>
SailfishOS	B-Operating_System
uses	O
Wayland	B-Language
only	O
as	O
it	O
does	O
n't	O
have	O
X11.AndroidQt	O
for	O
Android	B-Application
(	O
formerly	O
known	O
as	O
Necessitas	O
)	O
.Embedded	O
LinuxQt	O
for	O
embedded	B-Application
platforms	O
:	O
personal	B-Application
digital	I-Application
assistant	I-Application
,	O
smartphone	B-Application
,	O
etc	O
.	O
</s>
<s>
Exists	O
as	O
multiple	B-Operating_System
platforms	I-Operating_System
depending	O
on	O
display	O
technology	O
.	O
</s>
<s>
DirectFB	B-Application
,	O
LinuxFB	B-Language
and	O
EGLFS	O
(	O
EGL	B-Application
Full	O
Screen	O
)	O
.	O
</s>
<s>
Microsoft	O
platformsWindowsQt	O
for	O
Microsoft	B-Device
Windows	I-Device
7	I-Device
,	O
8	B-Application
and	O
10Windows	O
RTSupport	O
for	O
WinRT-based	O
Windows	B-Operating_System
10	I-Operating_System
Mobile	I-Operating_System
apps	O
and	O
Windows	B-Operating_System
10	I-Operating_System
IoT	O
Apple	O
platformsmacOSQt	O
for	O
Apple	O
macOS	B-Application
;	O
supports	O
applications	B-Application
on	O
CocoaiOSQt	O
for	O
iOS	B-Application
platforms	O
(	O
iPhone	B-Device
,	O
iPad	B-Device
)	O
Other	O
embedded	B-Application
platformsIntegrityQt	O
for	O
IntegrityQNXQt	O
for	O
QNXVxWorksQt	O
for	O
VxWorks	B-Operating_System
.	O
</s>
<s>
Only	O
available	O
under	O
a	O
proprietary	B-Application
(	O
commercial	O
)	O
license	O
.	O
</s>
<s>
Qt	B-Language
5.5	O
.	O
</s>
<s>
After	O
Nokia	O
opened	O
the	O
Qt	B-Language
source	O
code	O
to	O
the	O
community	O
on	O
Gitorious	B-Application
,	O
various	O
ports	O
appeared	O
.	O
</s>
<s>
There	O
are	O
also	O
some	O
ports	O
of	O
Qt	B-Language
that	O
may	O
be	O
available	O
,	O
but	O
are	O
not	O
supported	O
anymore	O
.	O
</s>
<s>
These	O
platforms	O
are	O
listed	O
in	O
List	B-Language
of	I-Language
platforms	I-Language
supported	I-Language
by	I-Language
Qt	I-Language
.	O
</s>
<s>
See	O
also	O
there	O
for	O
current	O
community	O
support	O
for	O
other	O
lesser	O
known	O
platforms	O
,	O
such	O
as	O
SailfishOS	B-Operating_System
.	O
</s>
<s>
Qt	B-Language
is	O
available	O
under	O
the	O
following	O
free	B-License
software	I-License
licenses	I-License
:	O
GPL	B-License
2.0	O
,	O
GPL	B-License
3.0	O
,	O
LGPL	B-Application
3.0	I-Application
and	O
LGPL	B-Application
2.1	I-Application
(	O
with	O
Qt	B-Language
special	O
exception	O
)	O
.	O
</s>
<s>
Note	O
that	O
some	O
modules	O
are	O
available	O
only	O
under	O
a	O
GPL	B-License
license	I-License
,	O
which	O
means	O
that	O
applications	B-Application
which	O
link	O
to	O
these	O
modules	O
need	O
to	O
comply	O
with	O
that	O
license	O
.	O
</s>
<s>
In	O
addition	O
,	O
Qt	B-Language
has	O
always	O
been	O
available	O
under	O
a	O
commercial	O
license	O
,	O
like	O
the	O
Qt	B-Language
Commercial	O
License	O
,	O
that	O
allows	O
developing	O
proprietary	B-Application
applications	B-Application
with	O
no	O
restrictions	O
on	O
licensing	O
.	O
</s>
<s>
Qt	B-Language
comes	O
with	O
its	O
own	O
set	O
of	O
tools	O
to	O
ease	O
cross-platform	B-Operating_System
development	O
,	O
which	O
can	O
otherwise	O
be	O
cumbersome	O
due	O
to	O
different	O
set	O
of	O
development	B-Application
tools	I-Application
.	O
</s>
<s>
Qt	B-Language
Creator	I-Language
is	O
a	O
cross-platform	B-Operating_System
IDE	B-Application
for	O
C++	B-Language
and	O
QML	B-Language
.	O
</s>
<s>
Qt	B-Language
Designer	I-Language
's	O
GUI	B-Application
layout/design	O
functionality	O
is	O
integrated	O
into	O
the	O
IDE	B-Application
,	O
although	O
Qt	B-Language
Designer	I-Language
can	O
still	O
be	O
started	O
as	O
a	O
standalone	O
tool	O
.	O
</s>
<s>
In	O
addition	O
to	O
Qt	B-Language
Creator	I-Language
,	O
Qt	B-Language
provides	O
qmake	B-Language
,	O
a	O
cross-platform	B-Operating_System
build	B-Application
script	I-Application
generation	I-Application
tool	I-Application
that	O
automates	O
the	O
generation	O
of	O
Makefiles	O
for	O
development	O
projects	O
across	O
different	O
platforms	O
.	O
</s>
<s>
There	O
are	O
other	O
tools	O
available	O
in	O
Qt	B-Language
,	O
including	O
the	O
Qt	B-Language
Designer	I-Language
interface	O
builder	O
and	O
the	O
Qt	B-Language
Assistant	O
help	O
browser	O
(	O
which	O
are	O
both	O
embedded	B-Application
in	O
Qt	B-Language
Creator	I-Language
)	O
,	O
the	O
Qt	B-Language
Linguist	O
translation	O
tool	O
,	O
uic	O
(	O
user	O
interface	O
compiler	O
)	O
,	O
and	O
moc	O
(	O
Meta-Object	O
Compiler	O
)	O
.	O
</s>
<s>
In	O
the	O
summer	O
of	O
1990	O
,	O
Haavard	O
Nord	O
and	O
Eirik	O
Chambe-Eng	O
(	O
the	O
original	O
developers	O
of	O
Qt	B-Language
and	O
the	O
CEO	O
and	O
President	O
,	O
respectively	O
,	O
of	O
Trolltech	O
)	O
were	O
working	O
together	O
on	O
a	O
database	O
application	O
for	O
ultrasound	O
images	O
written	O
in	O
C++	B-Language
and	O
running	O
on	O
Mac	B-Application
OS	I-Application
,	O
Unix	B-Application
,	O
and	O
Microsoft	B-Application
Windows	I-Application
.	O
</s>
<s>
They	O
began	O
development	O
of	O
"	O
Qt	B-Language
"	O
in	O
1991	O
,	O
three	O
years	O
before	O
the	O
company	O
was	O
incorporated	O
as	O
Quasar	O
Technologies	O
,	O
then	O
changed	O
the	O
name	O
to	O
Troll	O
Tech	O
and	O
then	O
to	O
Trolltech	O
.	O
</s>
<s>
The	O
toolkit	O
was	O
called	O
Qt	B-Language
because	O
the	O
letter	O
Q	B-Algorithm
looked	O
appealing	O
in	O
Haavard	O
's	O
Emacs	B-Application
typeface	O
,	O
and	O
"	O
t	O
"	O
was	O
inspired	O
by	O
Xt	B-Language
,	O
the	O
X	B-Language
toolkit	I-Language
.	O
</s>
<s>
The	O
first	O
two	O
versions	O
of	O
Qt	B-Language
had	O
only	O
two	O
flavors	O
:	O
Qt/X11	O
for	O
Unix	B-Application
and	O
Qt/Windows	O
for	O
Windows	O
.	O
</s>
<s>
On	O
20	O
May	O
1995	O
Troll	O
Tech	O
publicly	O
released	O
Qt	B-Language
0.90	O
for	O
X11/Linux	O
with	O
the	O
source	O
code	O
under	O
the	O
Qt	B-Language
Free	O
Edition	O
License	O
.	O
</s>
<s>
This	O
license	O
was	O
viewed	O
as	O
not	O
compliant	O
with	O
the	O
free	B-License
software	I-License
definition	O
by	O
Free	B-Operating_System
Software	I-Operating_System
Foundation	I-Operating_System
because	O
,	O
while	O
the	O
source	O
was	O
available	O
,	O
it	O
did	O
not	O
allow	O
the	O
redistribution	O
of	O
modified	O
versions	O
.	O
</s>
<s>
Controversy	O
erupted	O
around	O
1998	O
when	O
it	O
became	O
clear	O
that	O
the	O
K	B-Application
Desktop	I-Application
Environment	I-Application
was	O
going	O
to	O
become	O
one	O
of	O
the	O
leading	O
desktop	B-Device
environments	O
for	O
Linux	B-Application
.	O
</s>
<s>
As	O
it	O
was	O
based	O
on	O
Qt	B-Language
,	O
many	O
people	O
in	O
the	O
free	B-License
software	I-License
movement	O
worried	O
that	O
an	O
essential	O
piece	O
of	O
one	O
of	O
their	O
major	O
operating	O
systems	O
would	O
be	O
proprietary	B-Application
.	O
</s>
<s>
The	O
Windows	O
platform	O
was	O
available	O
only	O
under	O
a	O
proprietary	B-Application
license	I-Application
,	O
which	O
meant	O
free/open	O
source	O
applications	B-Application
written	O
in	O
Qt	B-Language
for	O
X11	B-Operating_System
could	O
not	O
be	O
ported	O
to	O
Windows	O
without	O
purchasing	O
the	O
proprietary	B-Application
edition	O
.	O
</s>
<s>
With	O
the	O
release	O
of	O
version	O
2.0	O
of	O
the	O
toolkit	O
in	O
mid-1999	O
,	O
the	O
license	O
was	O
changed	O
to	O
the	O
Q	B-Language
Public	I-Language
License	I-Language
(	O
QPL	B-Language
)	O
,	O
a	O
free	B-License
software	I-License
license	I-License
,	O
but	O
one	O
regarded	O
by	O
the	B-Operating_System
Free	I-Operating_System
Software	I-Operating_System
Foundation	I-Operating_System
as	O
incompatible	O
with	O
the	O
GPL	B-License
.	O
</s>
<s>
Compromises	O
were	O
sought	O
between	O
KDE	B-Application
and	O
Trolltech	O
whereby	O
Qt	B-Language
would	O
not	O
be	O
able	O
to	O
fall	O
under	O
a	O
more	O
restrictive	O
license	O
than	O
the	O
QPL	B-Language
,	O
even	O
if	O
Trolltech	O
was	O
bought	O
out	O
or	O
went	O
bankrupt	O
.	O
</s>
<s>
This	O
led	O
to	O
the	O
creation	O
of	O
the	O
KDE	B-Application
Free	O
Qt	B-Language
foundation	O
,	O
which	O
guarantees	O
that	O
Qt	B-Language
would	O
fall	O
under	O
a	O
BSD-style	B-Operating_System
license	I-Operating_System
should	O
no	O
free/open	O
source	O
version	O
of	O
Qt	B-Language
be	O
released	O
during	O
12	O
months	O
.	O
</s>
<s>
In	O
2000	O
,	O
Qt/X11	O
2.2	O
was	O
released	O
under	O
the	O
GPL	B-License
v2	O
,	O
ending	O
all	O
controversy	O
regarding	O
GPL	B-License
compatibility	O
.	O
</s>
<s>
At	O
the	O
end	O
of	O
2001	O
,	O
Trolltech	O
released	O
Qt	B-Language
3.0	O
,	O
which	O
added	O
support	O
for	O
Mac	B-Application
OS	I-Application
X	B-Operating_System
(	O
now	O
known	O
as	O
macOS	B-Application
)	O
.	O
</s>
<s>
The	O
Mac	B-Application
OS	I-Application
X	B-Operating_System
support	O
was	O
available	O
only	O
in	O
the	O
proprietary	B-Application
license	I-Application
until	O
June	O
2003	O
,	O
when	O
Trolltech	O
released	O
Qt	B-Language
3.2	O
with	O
Mac	B-Application
OS	I-Application
X	B-Operating_System
support	O
available	O
under	O
the	O
GPL	B-License
.	O
</s>
<s>
In	O
2002	O
,	O
members	O
of	O
the	O
KDE	B-Operating_System
on	I-Operating_System
Cygwin	I-Operating_System
project	O
began	O
porting	O
the	O
GPL	B-License
licensed	O
Qt/X11	O
code	O
base	O
to	O
Windows	O
.	O
</s>
<s>
This	O
was	O
in	O
response	O
to	O
Trolltech	O
's	O
refusal	O
to	O
license	O
Qt/Windows	O
under	O
the	O
GPL	B-License
on	O
the	O
grounds	O
that	O
Windows	O
was	O
not	O
a	O
free/open	O
source	O
software	O
platform	O
.	O
</s>
<s>
This	O
was	O
resolved	O
when	O
Trolltech	O
released	O
Qt	B-Language
4.0	O
also	O
for	O
Windows	O
under	O
the	O
GPL	B-License
in	O
June	O
2005	O
.	O
</s>
<s>
Qt4	B-Language
supported	O
the	O
same	O
set	O
of	O
platforms	O
in	O
the	O
free	O
software/open	O
source	O
editions	O
as	O
in	O
the	O
proprietary	B-Application
edition	O
,	O
so	O
it	O
is	O
possible	O
,	O
with	O
Qt	B-Language
4.0	O
and	O
later	O
releases	O
,	O
to	O
create	O
GPL-licensed	O
free/open	O
source	O
applications	B-Application
using	O
Qt	B-Language
on	O
all	O
supported	O
platforms	O
.	O
</s>
<s>
The	O
GPL	B-License
v3	O
with	O
special	O
exception	O
was	O
later	O
added	O
as	O
an	O
added	O
licensing	O
option	O
.	O
</s>
<s>
The	O
GPL	B-License
exception	O
allows	O
the	O
final	O
application	O
to	O
be	O
licensed	O
under	O
various	O
GPL-incompatible	O
free	O
software/open	O
source	O
licenses	O
such	O
as	O
the	O
Mozilla	B-License
Public	I-License
License	I-License
1.1	O
.	O
</s>
<s>
Nokia	O
acquired	O
Trolltech	O
ASA	O
on	O
17	O
June	O
2008	O
and	O
changed	O
the	O
name	O
first	O
to	O
Qt	B-Language
Software	I-Language
,	O
then	O
to	O
Qt	B-Language
Development	O
Frameworks	O
.	O
</s>
<s>
Nokia	O
focused	O
on	O
turning	O
Qt	B-Language
into	O
the	O
main	O
development	O
platform	O
for	O
its	O
devices	O
,	O
including	O
a	O
port	O
to	O
the	O
Symbian	B-Language
S60	I-Language
platform	O
.	O
</s>
<s>
Version	O
1.0	O
of	O
the	O
Nokia	O
Qt	B-Language
SDK	O
was	O
released	O
on	O
23	O
June	O
2010	O
.	O
</s>
<s>
The	O
source	O
code	O
was	O
made	O
available	O
over	O
Gitorious	B-Application
,	O
a	O
community	O
oriented	O
git	B-Application
source	O
code	O
repository	O
,	O
with	O
a	O
goal	O
of	O
creating	O
a	O
broader	O
community	O
using	O
and	O
improving	O
Qt	B-Language
.	O
</s>
<s>
On	O
14	O
January	O
2009	O
,	O
Qt	B-Language
version	O
4.5	O
added	O
another	O
option	O
,	O
the	O
LGPL	B-Application
,	O
to	O
make	O
Qt	B-Language
more	O
attractive	O
for	O
both	O
non-GPL	O
open	B-License
source	I-License
projects	O
and	O
closed	O
applications	B-Application
.	O
</s>
<s>
In	O
February	O
2011	O
,	O
Nokia	O
announced	O
its	O
decision	O
to	O
drop	O
Symbian	B-Operating_System
technologies	O
and	O
base	O
their	O
future	O
smartphones	B-Application
on	O
the	O
Windows	B-Protocol
Phone	I-Protocol
platform	O
instead	O
(	O
and	O
since	O
then	O
support	O
for	O
that	O
platform	O
has	O
also	O
been	O
dropped	O
)	O
.	O
</s>
<s>
One	O
month	O
later	O
,	O
Nokia	O
announced	O
the	O
sale	O
of	O
Qt	B-Language
's	O
commercial	O
licensing	O
and	O
professional	O
services	O
to	O
Digia	O
,	O
with	O
the	O
immediate	O
goal	O
of	O
taking	O
Qt	B-Language
support	O
to	O
Android	B-Application
,	O
iOS	B-Application
and	O
Windows	B-Application
8	I-Application
platforms	O
,	O
and	O
to	O
continue	O
focusing	O
on	O
desktop	B-Device
and	O
embedded	B-Application
development	O
,	O
although	O
Nokia	O
was	O
to	O
remain	O
the	O
main	O
development	O
force	O
behind	O
the	O
framework	O
at	O
that	O
time	O
.	O
</s>
<s>
In	O
March	O
2011	O
,	O
Nokia	O
sold	O
the	O
commercial	O
licensing	O
part	O
of	O
Qt	B-Language
to	O
Digia	O
,	O
creating	O
Qt	B-Language
Commercial	O
.	O
</s>
<s>
In	O
August	O
2012	O
,	O
Digia	O
announced	O
that	O
it	O
would	O
acquire	O
Qt	B-Language
from	O
Nokia	O
.	O
</s>
<s>
The	O
Qt	B-Language
team	O
at	O
Digia	O
started	O
their	O
work	O
in	O
September	O
2012	O
.	O
</s>
<s>
They	O
released	O
Qt	B-Language
5.0	O
within	O
a	O
month	O
and	O
newer	O
versions	O
every	O
six	O
months	O
with	O
new	O
features	O
and	O
additional	O
supported	O
platforms	O
.	O
</s>
<s>
In	O
September	O
2014	O
,	O
Digia	O
transferred	O
the	O
Qt	B-Language
business	O
and	O
copyrights	O
to	O
their	O
wholly	O
owned	O
subsidiary	O
,	O
The	O
Qt	B-Language
Company	O
,	O
which	O
owns	O
25	O
brands	O
related	O
to	O
Qt	B-Language
.	O
</s>
<s>
In	O
May	O
2016	O
,	O
Digia	O
and	O
Qt	B-Language
demerged	O
completely	O
into	O
two	O
independent	O
companies	O
.	O
</s>
<s>
Qt	B-Language
5	O
was	O
officially	O
released	O
on	O
19	O
December	O
2012	O
.	O
</s>
<s>
This	O
new	O
version	O
marked	O
a	O
major	O
change	O
in	O
the	O
platform	O
,	O
with	O
hardware-accelerated	O
graphics	O
,	O
QML	B-Language
and	O
JavaScript	B-Language
playing	O
a	O
major	O
role	O
.	O
</s>
<s>
The	O
traditional	O
C++	B-Language
-only	O
QWidgets	O
continued	O
to	O
be	O
supported	O
,	O
but	O
did	O
not	O
benefit	O
from	O
the	O
performance	O
improvements	O
available	O
through	O
the	O
new	O
architecture	O
.	O
</s>
<s>
Qt	B-Language
5	O
brings	O
significant	O
improvements	O
to	O
the	O
speed	O
and	O
ease	O
of	O
developing	O
user	O
interfaces	O
.	O
</s>
<s>
Framework	O
development	O
of	O
Qt	B-Language
5	O
moved	O
to	O
open	O
governance	O
at	O
qt-project.org,	O
which	O
made	O
it	O
possible	O
for	O
developers	O
outside	O
Digia	O
to	O
submit	O
patches	O
for	O
review	O
.	O
</s>
<s>
Aside	O
from	O
The	O
Qt	B-Language
Company	O
,	O
many	O
organizations	O
and	O
individuals	O
using	O
Qt	B-Language
as	O
their	O
development	O
platform	O
participate	O
in	O
the	O
open	B-License
development	I-License
of	O
Qt	B-Language
via	O
the	O
Qt	B-Language
Project	I-Language
.	O
</s>
<s>
One	O
such	O
Qt	B-Language
contributor	O
is	O
Klarälvdalens	O
Datakonsult	O
AB	O
,	O
a	O
Swedish	O
Qt	B-Language
consulting	O
company	O
.	O
</s>
<s>
Together	O
with	O
RIM/BlackBerry	O
,	O
KDAB	O
is	O
maintaining	O
the	O
QNX	B-Operating_System
and	O
BlackBerry	B-Application
10	I-Application
ports	O
of	O
Qt	B-Language
.	O
</s>
<s>
Another	O
participator	O
is	O
Intel	O
,	O
contributing	O
for	O
example	O
Wayland	B-Language
support	O
.	O
</s>
<s>
AudioCodes	O
maintains	O
IBM	B-Protocol
ClearCase	I-Protocol
support	O
in	O
Qt	B-Language
Creator	I-Language
.	O
</s>
<s>
As	O
a	O
heavy	O
user	O
of	O
Qt	B-Language
,	O
the	O
KDE	B-Application
project	O
submits	O
many	O
patches	O
and	O
features	O
from	O
its	O
developer	O
library	O
KDE	B-Language
Frameworks	I-Language
back	O
to	O
Qt	B-Language
.	O
</s>
