Copyleft/guide Changeset - 1d71dbc290c1

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@@ -1313,4 +1313,4 @@ So ends the terms and conditions of the GNU General Public License.

As we have seen in our consideration of the GPL, its text is specifically

designed to cover all possible deriviative works under copyright law.  Our

goal in desiging GPL was to make sure that any derivative work of GPL'd

designed to cover all possible derivative works under copyright law.  Our

goal in designing GPL was to make sure that any derivative work of GPL'd

software was itself released under GPL when distributed.  Reaching as far

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@@ -1319,3 +1319,3 @@ as copyright law will allow is the most direct way to reach that goal.

However, while the strategic goal is to bring as much Free Software into

the world as possible, particular tatical situations of software freedom

the world as possible, particular tactical situations of software freedom

dictate different means.  Extending the copyleft effect as far as

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@@ -1332,3 +1332,3 @@ needed was when work began on the GNU C Library.  The GNU C Library would

be (and today, now is) a drop-in replacement for existing C Libraries.  On

a Unix-like operating system, C is the linga franca and the C library is

a Unix-like operating system, C is the lingua franca and the C library is

an essential component for all programs.  It is extremely difficult to

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@@ -1336,3 +1336,3 @@ construct a program that will run with ease on a Unix-like operating

system without making use of services provided by the GNU C Library --

even if the program is written in a langauge other than C\@.  Effectively,

even if the program is written in a language other than C\@.  Effectively,

all user application programs that run on any modern Unix-like system must

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@@ -1341,3 +1341,3 @@ make use of the C Library.

By the time work began on the GNU implementation of the C Library, there

were already many C libraries in existance from a variety of vendors.

were already many C libraries in existence from a variety of vendors.

Every proprietary Unix vendor had one, and many third parties produced

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@@ -1370,3 +1370,3 @@ where many C Libraries already exist, many of which could easily be ported

to GNU/Linux, a GPL'd glibc would be unlikely to succeed.  Proprietary

vendors would see the exellent opportunity to license their C libraries to

vendors would see the excellent opportunity to license their C libraries to

anyone who wished to write proprietary software for GNU/Linux systems.

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@@ -1382,3 +1382,3 @@ The Lesser GPL was first conceived to handle this scenario.  It was clear

that the existence of proprietary applications for GNU/Linux was

inevitable.  Since there were so many C libraries already in existance, a

inevitable.  Since there were so many C libraries already in existence, a

new one under GPL would not stop that tide.  However, if the new C library

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@@ -1392,3 +1392,3 @@ the C library.

There was no way the license of glibc could stop or even slow the creation

of propreitary applications on GNU/Linux.  However, loosening the

of proprietary applications on GNU/Linux.  However, loosening the

restrictions on the licensing of glibc was able to ensure that nearly all

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@@ -1408,3 +1408,3 @@ the LGPL is helpful when studying the license.

Much of the text of the LGPL is identitcal to the GPL\@.  As we begin our

Much of the text of the LGPL is identical to the GPL\@.  As we begin our

discussion of the LGPL, we will first eliminate the sections that are

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@@ -1431,3 +1431,3 @@ LGPL's \S 11 is GPL's \S 7.  As discussed, it is used to ensure that

other claims and legal realities, such as patent licenses and court

judgements, do not trump the rights and permissions granted by these

judgments, do not trump the rights and permissions granted by these

licenses, and requires that distribution be halted if such a trump is

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@@ -1437,3 +1437,3 @@ LGPL's \S 12 adds the same features as GPL's \S 8.  These sections are

used to allow original copyright holders to forbid distribution in

countries with draconian laws that would otherwise contridict these

countries with draconian laws that would otherwise contradict these

licenses.

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@@ -1450,5 +1450,5 @@ identical; thus LGPL's \S 15 and \S 16 are the same as GPL's \S 11 and \S

Thus, as we see, the entire latter half of the license is identical.

The parts which set up the legal boundries and meta-rules for the license

The parts which set up the legal boundaries and meta-rules for the license

are the same.  It is our intent that the two licenses operate under the

same legal meachanisms and are enforced precisely the same way.

same legal mechanisms and are enforced precisely the same way.

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@@ -1459,3 +1459,3 @@ derivatives.  Since we simply do not allow the license to stretch as far

as copyright law does regarding what derivative works must be relicensed

under the same terms, we must go further to explain which dervative works

under the same terms, we must go further to explain which derivative works

we will allow to be proprietary.  Thus, we'll see that the front matter

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@@ -1468,3 +1468,3 @@ Most of LGPL's Preamble is identical, but the last seven paragraphs

introduce the concepts and reasoning behind creation of the license,

persenting a more generalized and briefer version of the story with which

presenting a more generalized and briefer version of the story with which

we began our consideration of LGPL\@.

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@@ -1524,7 +1524,7 @@ the binary is created) or at runtime (when the binary -- including library

and main program both -- is loaded into memory by the user).  In GPL,

binary derivative works are controled by the terms of the license (in GPL

binary derivative works are controlled by the terms of the license (in GPL

\S 3), and distributors of such binary derivatives must release full

correesponding source under terms of GPL\@.

corresponding source under terms of GPL\@.

In the case of LGPL, these are preceisely the types of derivative works

In the case of LGPL, these are precisely the types of derivative works

we wish to permit.  This scenario, defined in LGPL as ``a work that uses

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@@ -1532,4 +1532,2 @@ the library'', works as follows:

\begin{itemize}

\newcommand{\workl}{$\mathcal{L}$}

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@@ -1537,3 +1535,5 @@ the library'', works as follows:

\item A new copyright holder creates a separate and independant work,

\begin{itemize}

\item A new copyright holder creates a separate and independent work,

  \worki{}, that makes interface calls (e.g., function calls) to the

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@@ -1541,3 +1541,3 @@ the library'', works as follows:

  party.  Note that since \worki{} and \workl{} are separate and

  indepedant works, there is no copyright obligation on this new copyright

  independent works, there is no copyright obligation on this new copyright

  holder with regard to the licensing of \worki{}, at least with regard to

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@@ -1560,8 +1560,8 @@ use the library'' in detail in Section~\ref{FIXME}.  For now, focus on the

logic related to how the LGPL places requirements on the license of

\lplusi{}.  Note, first of all, the similarity between this explination

\lplusi{}.  Note, first of all, the similarity between this explanation

and that in Section~\ref{separate-and-independent}, which discussed the

combining otherwise separate and independant works with GPL'd code.

combining otherwise separate and independent works with GPL'd code.

Effectively, what LGPL is doing is saying that when a new work is

otherwise separate and independant, but has interface calls out to an

LGPL'ed library, then it is considered a ``work that uses the library''.

otherwise separate and independent, but has interface calls out to an

LGPL'd library, then it is considered a ``work that uses the library''.

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@@ -1569,3 +1569,3 @@ In addition, the only reason that LGPL has any control over the licensing

of a ``work that uses the library'' is for the same reason that GPL has

some say over separate and independant works.  Namely, such controls exist

some say over separate and independent works.  Namely, such controls exist

because the {\em binary combination\/} (\lplusi{}) that must be created to

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@@ -1577,6 +1577,6 @@ a ``work that uses the library'' under LGPL is as follows:

\begin{emumerate}

\begin{enumerate}

\item Is the source code of the new copyrighted work, \worki{}, a

  completely independant work that stands by itself, and includes no

  completely independent work that stands by itself, and includes no

  source code from \workl{}?

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@@ -1586,3 +1586,3 @@ a ``work that uses the library'' under LGPL is as follows:

  (runtime) linking, to create a new binary work, \lplusi{}?

\end{emumerate}

\end{enumerate}

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@@ -1606,3 +1606,3 @@ in the same sense that GPL does.

Most typically, one creates a ``work based on the library'' by directly

modifing the source of the library.  Such a work could also be created by

modifying the source of the library.  Such a work could also be created by

tightly integrating new software with the library.  The lines are no doubt

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@@ -1639,3 +1639,3 @@ a specific set of works that were based on the library.  Once such

distinctions are established, the licensing for each component can be

considered independantly and the LGPL applied to each work as prescribed.

considered independently and the LGPL applied to each work as prescribed.

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@@ -1668,3 +1668,3 @@ Specifically, while we know that a ``work that uses the library'' is one

whose final binary is a derivative work, but whose source is not, there

are cases where the object code --- that intermmediate step between source

are cases where the object code --- that intermediate step between source

and final binary --- is a derivative work created by copying verbatim code

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@@ -1672,8 +1672,8 @@ from the LGPL'd software.

For effeciency, when a compiler turns source code into object code, it

For efficiency, when a compiler turns source code into object code, it

sometimes places literal portions of the copyrighted library code into the

object code for an otherwise separate independant work.  In the normal

object code for an otherwise separate independent work.  In the normal

scenario, the derivative would not be created until final assembly and

linking of the executible occured.  However, when the compiler does this

effeciency optimization, at the intermediate object code step, a

linking of the executable occurred.  However, when the compiler does this

efficiency optimization, at the intermediate object code step, a

derivative work is created.

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@@ -1685,3 +1685,3 @@ based on the library''.  However, since the compiler copies verbatim,

copyrighted portions of the library into the object code for the otherwise

separate and independant work, it would actually cause that object file a

separate and independent work, it would actually cause that object file a

``work based on the library''.  It is not FSF's intent that a mere

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@@ -1696,3 +1696,3 @@ idiosyncrasy, because that particular vendor wanted to ship object code

(rather than final binaries) to their customers and were worried about

this edge condition.  The intent of clarifing this edge condition is

this edge condition.  The intent of clarifying this edge condition is

primarily to quell the worries of software engineers who understand the

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@@ -1714,7 +1714,70 @@ available.  The work that ``uses'' the library need not be provided in

source form.  However, there are also conditions in LGPL \S 6 to make sure

that a user who wishes to modify or udpate the library can do so.

that a user who wishes to modify or update the library can do so.

LGPL \S 6 lists five choices with regard to supplying library source and

the freedom to modify that library source the users.  We will first

consider the option given by \S 6(b), which describes the most common way

that is currently used for LGPL compliance on a ``work that uses the

library''.

\S 6(b) allows the distributor of a ``work that uses the library'' to

simply use a dynamically linked, shared library mechanism to link with the

library.  This is by far the easiest and most straightforward option for

distribution.  In this case, the executable of the work that uses the

library will contain only the ``stub code'' that is put in place by the

shared library mechanism, and at runtime the executable will combine with

the shared version of the library already resident on the user's computer.

If such a mechanism is used, it must allow the user to upgrade and

replace the library with interface-compatible versions and still be able

to use the ``work that use the library''.  However, all modern shared

library mechanisms function as such, and thus \S 6(b) is the simplest

option, since it does not even require that the distributor of the ``work

based on the library'' ship copies of the library itself.

\S 6(a) is the option to use when, for some reason, a shared library

mechanism cannot be used.  It requires that the source for the library be

included, in the typical GPL fashion, but it also has a requirement beyond

that.  The user must be able to exercise her freedom to modify the library

to its fullest extent, and that means recombining it with the ``work based

on the library''.  If the full binary is linked without a shared library

mechanism, the user must have available the object code for the ``worked

based on the library'', so that the user can relink the application and

build a new binary.

The remaining options in \S 6 are very similar to the other choices

provided by GPL \S 3.  There are some additions, and time does not permit

us in this course to go into those additional options.  In almost all

cases of distribution under LGPL, either \S 6(a) or \S 6(b) are exercised.

\section{Distribution of Works Based on the Library}

Essential, ``works based on the library'' must be distributed under the

same conditions as works under full GPL\@.  In fact, we note that LGPL's \S

2 is nearly identical in its terms and requirements to GPL's \S 2.  There

are again subtle differences and additions, which time does not permit us

to cover in this course.

\section{And the Rest}

The remaining variations between LGPL and GPL cover the following

conditions:

\begin{itemize}

LGPL \S 6 lists five choices

\item allowing a licensing ``upgrade'' from LGPL to GPL\@ (in LGPL \S 3),

\item binary distribution of the library only, covered in LGPL \S 4,

  which is effectively equivalent to LGPL \S 3, and

\item creating aggregates of libraries that are not derivative works of

  each other, and distributing them as a unit (in LGPL \S 7).

\end{itemize}

Due to time constraints, we cannot cover these additional terms in detail,

but they are mostly straightforward.  The key to understanding LGPL is

understanding the difference between a ``work based on the library'' and a

``work that uses the library''.  Once that distinction is clear, the

remainder of LGPL is close enough to GPL that the concepts discussed in

our more extensive GPL unit can be directly applied.

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@@ -2871,3 +2934,3 @@ That's all there is to it!

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