Licensing Debate

Are the EPL and GNU Incompatible?

Jessica Thornsby

Mike Milinkovich’s tips on licensing open source software.

Mike Milinkovich has posted his thoughts on the compatibility of the Eclipse
Public License (EPL) and the GNU General Public License (GPL) after
Andrea Antonello submitted an open letter on the subject.

Andrea Antonello expressed some confusion regarding licensing in
the open source community, and asked for some clarification on the
GPL and EPL in particular.

In Milinkovich’s reply, he explains that these licenses are
generally incompatible: “You may not link GPL and EPL code together
and distribute the result. It doesn’t matter if the linking is
dynamic, static or whatever.” However, there is still considerable
grey area. If the EPL and GPL components interact with each other
via pipes, sockets, or if Eclipse is running as an application on
top of GNU Linux then, according to Milinkovich this is an entirely
different scenario, which he does not discuss in his blog posting.
There is also the possibility to create a combination of EPL and
GPL plugins, which could not be lawfully distributed as a single
unit. Milinkovich writes that it is not possible to link a plugin,
licensed under the GPL, to an EPL-licensed code, and distribute the

Milinkovich urges Eclipse developers to use the EPL license for
their Eclipse plugins, although if a developer creates an Eclipse
plugin, they are not legally required to license it under the

Milinkovich concludes by pointing out that his blog post is
intended for “general guidance” only. “This post was not prepared
by an attorney nor is it in any way legal advice.”

Visitors to his blog have discussed the potential negative
consequences of licensing open source software in general. One
visitor points to a use case first raised by Antonello –
distributing a GPL-bundle with the Equinox runtime – which
Milinkovich implies isn’t possible. “This is really a huge and very
negative implication,” the visitor writes.

“Just because something is open source does not mean that a
developer can use it without regard to the license terms,”
Milinkovich replies, highlighting the inherent conflict between the
principles of open source software, and the reality of having to
obey certain licensing terms.

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