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Take the Free Software licensing quiz and test your knowledge of the
GPL and LGPL.
As this Quiz represents the legal opinions of the FSF (but is not legal
advice), only verbatim copying and redistribution is allowed.
Translations must be approved by the FSF; please write to firstname.lastname@example.org for details.
Joan writes a web browser and releases the source code under the
GPL on her web site. Fred gives a CD with binaries of Joan's
browser to his friend for her birthday. Which of the following
does NOT satisfy Fred's obligation to make source code
This issue is covered in detail in the GPL FAQ.
Now Fred makes modifications to Joan's web browser, and distributes
binaries on his web site. Which of the following fulfill Fred's obligation
to distribute the source code of the modified browser?
This issue is covered in detail in the GPL FAQ, and in sections 2 and 3 of the GPL.
Fred wishes to distribute Joan's browser linked to a third-party
module. The third party module has the following license:
"This code may be freely modified, copied and
distributed, so long as no fee is charged for it."
Would this violate the GPL?
You can find out about this issue in the GPL, section 6, and in
the Free Software
Peter creates a library called LibIdo licensed under the Lesser
General Public License. FooCorp distributes a modified version LibIdo
library linked to their proprietary program Frobber. Which of the
following is NOT an obligation of FooCorp?
You can find out about this issue in the LGPL, sections 2
Joan wants to distribute copies of her browser statically linked to
Postfix (a mail server), which is released under the IBM Public License, a GPL-incompatible Free Software license. Other
than Postfix, the browser includes only code on which Joan holds the
Should she grant an exception to the GPL for this?
You can find out about this issue in the GPL FAQ here,
FooCorp sells binaries of Joan's GPL'd web browser on CD without
source code. They include an offer to provide source code. Which of
the following offers fulfills their obligations under the GPL?
You can find out about this issue in the GPL, section 3b.
Patty creates a library, and releases it under the GPL. Many people
make improvements to this library, and submit them back to Patty, who
incorporates them into newer versions of the library. Now Patty wants
to make a proprietary version of this library. She makes two claims:
Because the original version was under the GPL, everyone who
made improvements automatically assigned copyright on those
improvements to Patty, so she doesn't need to ask permission
Because she is the copyright holder, she can relicense the
code retroactively, so nobody can distribute old versions under
the GPL anymore.
Are these claims true?
Section 4 of the GPL, explains the
conditions under which permission to distribute GPL'd software can be
revoked. Copyright law itself has more information.
FooCorp distributes Frobber linked against an unmodified version of
LibIdo. Does the LGPL require FooCorp to allow users to reverse
engineer Frobber for their own use?
Section 6 of the LGPL contains the
requirements for a "work that uses the library."
Now FooCorp modifies Joan's browser to include a technology they have
patented. They distribute this modified browser on CD. Are there any
requirements in the GPL on how they may license their applicable
Section 7 of the GPL explains patent