@@ -112,49 +112,49 @@ freedom community. While the GPL's requirements may initially appear
counter-intuitive to those more familiar with proprietary software
licenses, by comparison, its terms are in fact clear and quite favorable to
licensees. Indeed, the GPL's terms actually simplify compliance when
violations occur.
GPL violations occur (or, are compounded) most often when companies lack sound
practices for the incorporation of GPL'd components into their
internal development environment. This section introduces some best
practices for software tool selection, integration and distribution,
inspired by and congruent with software freedom methodologies. Companies should
establish such practices before building a product based on GPL'd
software.\footnote{This document addresses compliance with GPLv2,
GPLv3, LGPLv2, and LGPLv3. Advice on avoiding the most common
errors differs little for compliance with these four licenses.
\S~\ref{lgpl} discusses the key differences between GPL and LGPL
compliance.}
\section{Evaluate License Applicability}
\label{derivative-works}
Political discussion about the GPL often centers around the ``copyleft''
requirements of the license. Indeed, the license was designed primarily
to embody this licensing feature. Most companies adding non-trivial
features (beyond mere porting and bug-fixing) to GPL'd software (and
thereby invoking these requirements) are already well aware of their
more complex obligations under the license.\footnote{While, there has been much legal
more complex obligations under the license.\footnote{There has been much legal
discussion regarding copyleft and derivative works. In practical
reality, this issue is not relevant to the vast majority of companies
distributing GPL'd software. Those interested in this issue should study
\tutorialpartsplit{\textit{Detailed Analysis of the GNU GPL and Related
Licenses}'s Section on derivative works}{\S~\ref{derivative-works} of
this tutorial}.}
However, experienced GPL enforcers find that few redistributors'
compliance challenges relate directly to the copyleft provisions; this is
particularly true for most embedders. Instead, the distributions of GPL'd
systems most often encountered typically consist of a full operating system
including components under the GPL (e.g., Linux, BusyBox) and components
under the LGPL (e.g., the GNU C Library). Sometimes, these programs have
been patched or slightly improved by direct modification of their sources,
resulting unequivocally in a derivative work. Alongside these programs,
companies often distribute fully independent, proprietary programs,
developed from scratch, which are designed to run on the Free Software operating
system but do not combine with, link to, modify, derive from, or otherwise
create a combined work with
the GPL'd components.\footnote{However, these programs do often combine
with LGPL'd libraries. This is discussed in detail in \S~\ref{lgpl}.}
In the latter case, where the work is unquestionably a separate work of
creative expression, no copyleft provisions are invoked.