<s>
The	O
GNU	B-Application
Lesser	I-Application
General	I-Application
Public	I-Application
License	I-Application
(	O
LGPL	B-Application
)	O
is	O
a	O
free-software	B-License
license	I-License
published	O
by	O
the	B-Operating_System
Free	I-Operating_System
Software	I-Operating_System
Foundation	I-Operating_System
(	O
FSF	O
)	O
.	O
</s>
<s>
The	O
license	O
allows	O
developers	O
and	O
companies	O
to	O
use	O
and	O
integrate	O
a	O
software	O
component	O
released	O
under	O
the	O
LGPL	B-Application
into	O
their	O
own	O
(	O
even	O
proprietary	B-Application
)	O
software	O
without	O
being	O
required	O
by	O
the	O
terms	O
of	O
a	O
strong	O
copyleft	B-License
license	I-License
to	O
release	O
the	O
source	O
code	O
of	O
their	O
own	O
components	O
.	O
</s>
<s>
However	O
,	O
any	O
developer	O
who	O
modifies	O
an	O
LGPL-covered	O
component	O
is	O
required	O
to	O
make	O
their	O
modified	O
version	O
available	O
under	O
the	O
same	O
LGPL	B-Application
license	I-Application
.	O
</s>
<s>
For	O
proprietary	B-Application
software	I-Application
,	O
code	O
under	O
the	O
LGPL	B-Application
is	O
usually	O
used	O
in	O
the	O
form	O
of	O
a	O
shared	O
library	O
,	O
so	O
that	O
there	O
is	O
a	O
clear	O
separation	O
between	O
the	O
proprietary	B-Application
and	O
LGPL	B-Application
components	O
.	O
</s>
<s>
The	O
LGPL	B-Application
is	O
primarily	O
used	O
for	O
software	B-Library
libraries	I-Library
,	O
although	O
it	O
is	O
also	O
used	O
by	O
some	O
stand-alone	O
applications	O
.	O
</s>
<s>
The	O
LGPL	B-Application
was	O
developed	O
as	O
a	O
compromise	O
between	O
the	O
strong	O
copyleft	B-License
of	O
the	O
GNU	B-License
General	I-License
Public	I-License
License	I-License
(	O
GPL	B-License
)	O
and	O
more	O
permissive	B-License
licenses	I-License
such	O
as	O
the	O
BSD	B-Operating_System
licenses	I-Operating_System
and	O
the	B-License
MIT	I-License
License	I-License
.	O
</s>
<s>
The	O
word	O
"	O
Lesser	O
"	O
in	O
the	O
title	O
shows	O
that	O
the	O
LGPL	B-Application
does	O
not	O
guarantee	O
the	O
end	O
user	O
's	O
complete	O
freedom	O
in	O
the	O
use	O
of	O
software	O
;	O
it	O
only	O
guarantees	O
the	O
freedom	O
of	O
modification	O
for	O
components	O
licensed	O
under	O
the	O
LGPL	B-Application
,	O
but	O
not	O
for	O
any	O
proprietary	B-Application
components	O
.	O
</s>
<s>
The	O
license	O
was	O
originally	O
called	O
the	O
GNU	B-Application
Library	I-Application
General	I-Application
Public	I-Application
License	I-Application
and	O
was	O
first	O
published	O
in	O
1991	O
,	O
and	O
adopted	O
the	O
version	O
number	O
2	O
for	O
parity	O
with	O
GPL	B-License
version	O
2	O
.	O
</s>
<s>
The	O
LGPL	B-Application
was	O
revised	O
in	O
minor	O
ways	O
in	O
the	O
2.1	O
point	O
release	O
,	O
published	O
in	O
1999	O
,	O
when	O
it	O
was	O
renamed	O
the	O
GNU	B-Application
Lesser	I-Application
General	I-Application
Public	I-Application
License	I-Application
to	O
reflect	O
the	O
FSF	O
's	O
position	O
that	O
not	O
all	O
libraries	O
should	O
use	O
it	O
.	O
</s>
<s>
Version	O
3	O
of	O
the	O
LGPL	B-Application
was	O
published	O
in	O
2007	O
as	O
a	O
list	O
of	O
additional	O
permissions	O
applied	O
to	O
GPL	B-License
version	O
3	O
.	O
</s>
<s>
In	O
addition	O
to	O
the	O
term	O
"	O
work	O
based	O
on	O
the	O
Program	O
"	O
of	O
GPL	B-License
,	O
LGPL	B-Application
version	O
2	O
introduced	O
two	O
additional	O
clarification	O
terms	O
"	O
work	O
based	O
on	O
the	O
library	O
"	O
and	O
a	O
"	O
work	O
that	O
uses	O
the	O
library	O
"	O
.	O
</s>
<s>
LGPL	B-Application
version	O
3	O
partially	O
dropped	O
these	O
terms	O
.	O
</s>
<s>
The	O
main	O
difference	O
between	O
the	O
GPL	B-License
and	O
the	O
LGPL	B-Application
is	O
that	O
the	O
latter	O
allows	O
the	O
work	O
to	O
be	O
linked	O
with	O
(	O
in	O
the	O
case	O
of	O
a	O
library	O
,	O
"	O
used	O
by	O
"	O
)	O
a	O
non-(L )	O
GPLed	O
program	O
,	O
regardless	O
of	O
whether	O
it	O
is	O
licensed	O
under	O
a	O
license	O
of	O
GPL	B-License
family	O
or	O
other	O
licenses	O
.	O
</s>
<s>
In	O
LGPL	B-Application
2.1	I-Application
,	O
the	O
non-(L )	O
GPLed	O
program	O
can	O
then	O
be	O
distributed	O
under	O
any	O
terms	O
if	O
it	O
is	O
not	O
a	O
derivative	O
work	O
.	O
</s>
<s>
Whether	O
a	O
work	O
that	O
uses	O
an	O
LGPL	B-Application
program	O
is	O
a	O
derivative	O
work	O
or	O
not	O
is	O
a	O
legal	O
issue	O
.	O
</s>
<s>
A	O
standalone	O
executable	O
that	O
dynamically	O
links	O
to	O
a	O
library	O
through	O
a	O
.so	O
,	O
.dll	O
,	O
or	O
similar	O
medium	O
is	O
generally	O
accepted	O
as	O
not	O
being	O
a	O
derivative	O
work	O
as	O
defined	O
by	O
the	O
LGPL	B-Application
.	O
</s>
<s>
Paragraph	O
5	O
of	O
the	O
LGPL	B-Application
version	O
2.1	O
states	O
:	O
</s>
<s>
Essentially	O
,	O
if	O
it	O
is	O
a	O
"	O
work	O
that	O
uses	O
the	O
library	O
"	O
,	O
then	O
it	O
must	O
be	O
possible	O
for	O
the	O
software	O
to	O
be	O
linked	O
with	O
a	O
newer	O
version	O
of	O
the	O
LGPL-covered	O
program	O
.	O
</s>
<s>
Alternatively	O
,	O
a	O
statically	B-Library
linked	I-Library
library	I-Library
is	O
allowed	O
if	O
either	O
source	O
code	O
or	O
linkable	O
object	O
files	O
are	O
provided	O
.	O
</s>
<s>
One	O
feature	O
of	O
the	O
LGPL	B-Application
is	O
the	O
permission	O
to	O
sublicense	O
under	O
the	O
GPL	B-License
any	O
piece	O
of	O
software	O
which	O
is	O
received	O
under	O
the	O
LGPL	B-Application
(	O
see	O
section	O
3	O
of	O
the	O
LGPL	B-Application
version	O
2.1	O
,	O
and	O
section	O
2	O
option	O
b	O
of	O
the	O
LGPL	B-Application
version	O
3	O
)	O
.	O
</s>
<s>
Version	O
3	O
of	O
the	O
LGPL	B-Application
is	O
not	O
inherently	O
compatible	O
with	O
version	O
2	O
of	O
the	O
GPL	B-License
.	O
</s>
<s>
However	O
,	O
works	O
using	O
the	O
latter	O
that	O
have	O
given	O
permission	O
to	O
use	O
a	O
later	O
version	O
of	O
the	O
GPL	B-License
are	O
compatible	O
:	O
a	O
work	O
released	O
under	O
the	O
GPLv2	O
"	O
or	O
any	O
later	O
version	O
"	O
may	O
be	O
combined	O
with	O
code	O
from	O
a	O
LGPL	B-Application
version	O
3	O
library	O
,	O
with	O
the	O
combined	O
work	O
as	O
a	O
whole	O
falling	O
under	O
the	O
terms	O
of	O
the	O
GPLv3	O
.	O
</s>
<s>
The	O
former	O
name	O
GNU	B-Application
Library	I-Application
General	I-Application
Public	I-Application
License	I-Application
gave	O
some	O
the	O
impression	O
that	O
the	O
FSF	O
recommended	O
that	O
all	O
software	B-Library
libraries	I-Library
should	O
use	O
the	O
LGPL	B-Application
and	O
programs	O
should	O
use	O
the	O
GPL	B-License
.	O
</s>
<s>
In	O
1999	O
essay	O
Why	O
you	O
should	O
n't	O
use	O
the	O
Lesser	B-Application
GPL	I-Application
for	O
your	O
next	O
library	O
Richard	O
Stallman	O
explained	O
that	O
while	O
the	O
LGPL	B-Application
had	O
not	O
been	O
deprecated	B-General_Concept
,	O
one	O
should	O
not	O
necessarily	O
use	O
the	O
LGPL	B-Application
for	O
all	O
libraries	O
,	O
as	O
using	O
GPL	B-License
can	O
give	O
advantage	O
to	O
free-software	O
developers	O
.	O
</s>
<s>
For	O
example	O
,	O
Stallman	O
endorsed	O
the	O
use	O
of	O
BSD-style	B-Operating_System
license	I-Operating_System
by	O
the	O
Vorbis	B-Algorithm
project	O
in	O
its	O
libraries	O
in	O
2001	O
.	O
</s>
<s>
The	O
license	O
uses	O
terminology	O
which	O
is	O
mainly	O
intended	O
for	O
applications	O
written	O
in	O
the	O
C	B-Language
programming	I-Language
language	I-Language
or	O
its	O
family	O
.	O
</s>
<s>
Franz	O
Inc.	O
,	O
the	O
developers	O
of	O
Allegro	B-Language
Common	I-Language
Lisp	I-Language
,	O
published	O
their	O
own	O
preamble	O
to	O
the	O
license	O
to	O
clarify	O
terminology	O
in	O
the	O
Lisp	B-Language
context	O
.	O
</s>
<s>
The	O
LGPL	B-Application
with	O
this	O
preamble	O
is	O
sometimes	O
referred	O
to	O
as	O
the	O
LLGPL	O
.	O
</s>
<s>
In	O
addition	O
,	O
Ada	B-Language
has	O
a	O
special	O
feature	O
,	O
generics	O
,	O
which	O
may	O
prompt	O
the	O
use	O
of	O
the	O
GNAT	B-Application
Modified	I-Application
General	I-Application
Public	I-Application
License	I-Application
(	O
GMGPL	B-Application
)	O
:	O
it	O
allows	O
code	O
to	O
link	O
against	O
or	O
instantiate	O
GMGPL-covered	O
units	O
without	O
the	O
code	O
itself	O
becoming	O
covered	O
by	O
the	O
GPL	B-License
.	O
</s>
<s>
C++	B-Language
templates	O
and	O
header-only	B-Language
libraries	I-Language
have	O
the	O
same	O
problem	O
as	O
Ada	B-Language
generics	O
.	O
</s>
<s>
Version	O
3	O
of	O
the	O
LGPL	B-Application
addresses	O
such	O
cases	O
in	O
section	O
3	O
.	O
</s>
<s>
Some	O
concern	O
has	O
risen	O
about	O
the	O
suitability	O
of	O
object-oriented	O
classes	O
in	O
LGPL-licensed	O
code	O
being	O
inherited	B-Language
by	O
non-(L )	O
GPL	B-License
code	O
.	O
</s>
<s>
Clarification	O
is	O
given	O
on	O
the	O
official	O
GNU	B-Operating_System
website	O
:	O
</s>
<s>
The	O
LGPL	B-Application
does	O
not	O
contain	O
special	O
provisions	O
for	O
inheritance	B-Language
,	O
because	O
none	O
are	O
needed	O
.	O
</s>
<s>
Inheritance	B-Language
creates	O
derivative	O
works	O
in	O
the	O
same	O
way	O
as	O
traditional	O
linking	O
,	O
and	O
the	O
LGPL	B-Application
permits	O
this	O
type	O
of	O
derivative	O
work	O
in	O
the	O
same	O
way	O
as	O
it	O
permits	O
ordinary	O
function	O
calls	O
.	O
</s>
