obligations.  In general, they must refrain from imposing any additional

restrictions on downstream parties. Most typically, such compliance problems

arise from ``umbrella licenses:'' EULAs, or sublicenses that restrict

\S~\ref{GPLv3s10}).

Patent holders having claims reading on GPL'd works they distribute must

Fortunately, COGEOs regard GPL compliance failures as an opportunity to

improve compliance.  Every compliance failure downstream represents a loss of

developers' rights.  Their activity seeks to restore those rights, and

software. 

\chapter{Best Practices to Avoid Common Violations}

  incomplete, or is not delivered at all).

\item Requestors are ignored when they communicate with violator's published

\end{itemize}

This tutorial therefore focuses primarily on these issue.

source or binary form) of each licensed work.  Strangely, this requirement is

responsible for a surprisingly significant fraction of compliance errors; too

often, physical products lack required information about the presence of

can and should carry a copy of the license from the the source distribution

into the final binary firmware package for embedded products.  Such

automation usually achieves compliance regarding license inclusion

Thus, under the terms of LGPL, you must refrain from license terms on works

based on the licensed work that prohibit replacement of the licensed

LGPLv3 is not surprisingly easier to understand and examine from a compliance

lens, since the FSF was influenced in LGPLv3's drafting by questions and

A few stories abound in the GPL enforcement community that companies have

often formed beneficial consulting or employment relationships with

developers they first encountered through enforcement.  In some cases,

often, the communication channels opened in the course of the inquiry served

other and more fruitful purposes later.

the primary unit of consideration under most copyright rules -- is not a unit

of computer programming. In order to determine whether a ``routine'' an

``object'', a ``function'', a ``library'' or any other unit of software is

question that copyright law will not directly answer in the same technical

terms.

would get with a typical work not covered by a copyleft license.  Thus, to

say that this condition is any way unreasonable is simply ludicrous.

combined, then the obligations of copyleft do not extend to the work

separately distributed.  Thus, Far from attempting to extend copyleft beyond the

scope of copyright, the licenses explicitly recognize.

Thus, GPL recognizes what is outside its scope.  When a programmer's work is

be combined, then copyleft obligations do not extend to the independent work

separately distributed.  Thus, far from attempting to extend copyleft beyond

the scope of copyright, GPL explicitly limits the scope of copyleft to the

GPL does not, however (as is sometimes suggested) distinguish ``dynamic''

from ``static'' linking of program code.  It is occasionally suggested that a

alone, inherently outside the scope of copyleft on the main work.  This is a

misunderstanding.  When two software components are joined together to make

one work (whether a main and some library subroutines, two objects with their

only copyright license allowing you to copy, modify and distribute the

software.

provision\footnote{This section was substantially expanded for clarity and

  detail in \hyperref[GPLv3s10]{GPLv3~\S10}.}.  Each time you

from each original licensor to copy, distribute or modify the program subject

to the conditions of the license.  The redistributor need not take any

This places every copyright holder in the chain of descent of the code

in legal privity, or direct relationship, with every downstream

redistributor.  Two legal effects follow.  First, downstream parties

\item This provision allows limitations on the use of names of licensor for

  publicity purposes.  This provision also yields additional compatibility

  with non-copyleft Free Software licenses that prohibit the use of the

  advertising rights).  The third clause of the

  \href{http://opensource.org/licenses/BSD-3-Clause}{3-Clause BSD

  License}, for example, long considered de-facto compatible with GPLv2

\begin{itemize}

\item Grant of license to claims in contributor versions: GPLv3~\S11

  introduces an affirmative grant of rights to patent claims by those who

  aggressively asserting patents against users of code those parties have

  themselves modified --- in theory preventing betrayal by ``insiders'' of

  the copyleft community.  A contributor's patent claims necessarily

% FIXME-LATER: This text is likely redundant and a bit confusing.  Needs work

% to use.

%% that it does not suffer itself. Under many circumstances, this is an

%% acceptable outcome. If, however, A is the only possible source of the

%% program, by taking such a license and distributing in reliance on it, A is in

serve us. The GNU Lesser General Public License (``GNU LGPL'') was

designed as a solution for such situations.

The Lesser General Public License is sometimes described as a ``weak copyleft''

under non-free licenses, and is sometimes used in that fashion.

\section{The First LGPL'd Program}

compliantly taken from its context in a library and placed in a non-library

modified version or work based on the work.  For its part, LGPLv2~\S6 does

not provide an exception for this rule: a combination may be made of a

must continue to be structured as a library, and to that library the terms of

the license continue to apply.

\begin{quote}

\begin{enumerate}[label=4(d)(\arabic*):,ref=LGPLv3s4d\arabic*]

  \item uses at run time a copy of the library already present on

    the executable, and

  \item will operate properly with a modified version of