It is probably also worth noting that a few files are released under the GNU General Public License (GPL) without the exception clause, however these are not linked into the run-time environment and therefore pose no conflict with those files that carry the exception.
The exception clause is as follows:
If you choose to link software from Liquorice
with other files to produce an executable, this does not by itself cause
the resulting executable to be covered by the GNU General Public License.
Your use of the executable is in no way restricted on account of linking
the Liquorice code with it.
This exception does not however invalidate any other reason why the executable file might be covered by the GNU General Public License. This exception applies only to the code released by David J. Hudson and any other identified copyright holder under the name Liquorice. If you copy other code that is released by its copyright holder under the GNU General Public License into a copy of Liquorice, as the GNU General Public License permits, then this exception does not apply to the code that you add in this way. To avoid misleading anyone as to the status of such modified files, you must delete references to this exception notice from them. If you write modifications of your own
for Liquorice, it is you choice whether to permit this exception to apply
to your modifications. If you do not wish this, delete references
to this exception notice from the affected files.
|
You can use the code within Liquorice
in exactly the same way as any other GPL'd software. The GPL itself
describes what this means and many informed opinions have been published
to describe this.
The exception clause allows you to link non-GPL'd code with the Liquorice code without the non-GPL'd part becoming subject to the GPL. Whilst linking Liquorice with non-GPL'd
code does not mean that the non-GPL'd code takes on Liquorice's license,
similarly the act of linking does not mean that Liquorice becomes licensed
under any other terms that the non-GPL'd code may carry (unless suitable
written consent with respect to Liquorice is obtained first).
|
Generally the aim is that Liquorice may be used in any application, but that the part of that application that is Liquorice must remain subject to Liquorice's license. Modifications and the Liquorice sources on which they are based must remain freely available to users of that software, etc.
If a new file is created and linked with
existing Liquorice files then it will not need to be subject to Liquorice's
license unless a significant part of the code within that file is copied
from files that carry Liquorice's license. Whilst "significant" is very
difficult to define, a reasonable judgement would be that anything that
involves copying a block of more than 10 statements of C code from a Liquorice
file would tend to be significant. Clearly though this is just a
guideline and the copyright-holder should be consulted if you aren't too
sure.
During September 2000 it was pointed out that clause 6 of the LGPL presented a significant problem with respect to embedded applications where firmware was fuse protected. Having thought about this, it was also evident that the problem was even more serious for any application that might be built into a one-time-programmable, mask-ROM or custom ASIC device since by their very nature they cannot be reprogrammed.
After querying the situation with the Free Software Foundation, their suggestion was to adopt the license that they use for GUILE. GUILE is licensed with the intention of allowing it to be used as a part of non-GPL'd applications whilst still remaining free itself.
Having reviewed this suggestion, and deciding
that it seemed a good solution, it was decided that from 18th October 2000
all of the files within Liquorice that were previously licensed under the
LGPL should be re-licensed under these terms (GPL plus exception clause).
For the record, I will be using Liquorice
for some commercial work, and I am sure that I will not be able to make
all of it (the commercial stuff that is) freely available. Wherever I can
however I will do so.