Lesser GPL

I wish to develop a free application but later possibly make a pro version with additional features and sell that for about $20. I would like to know what restrictions the Lesser GPL places on me if my software includes another piece of software licensed under it.

Specifically I'd like to know:

1) If all of my software will need to be licensed under the Lesser GPL or if it will all need to be open source?

2) Does it just mean that the 'library' licensed under it must continue to be licensed under the Lesser GPL in the distribution of my software?

Who is Participating?
MysidiaConnect With a Mentor Commented:
I am not a lawyer.. for legal advise, you should perhaps consult one.. if you are plan on selling
a software product; the LGPL attempts to impose certain rules.

But see http://en.wikipedia.org/wiki/LGPL
and http://www.fsf.org/licenses/why-not-lgpl.html

"The GNU Project has two principal licenses to use for libraries. One is the GNU Library GPL; the other is the ordinary GNU GPL. The choice of license makes a big difference: using the Library GPL permits use of the library in proprietary programs; using the ordinary GPL for a library makes it available only for free programs."

The simple answer is that if you follow the rules set out by the license carefully, the LGPL is supposed to allow you to
use your library in proprietary software... some library facilities can be proprietary, some can be non-proprietary.

There are a few major requirements: for example, among other things, if you modify the library, you still have to distribute
source to that (the LGPL facilities are still under the LGPL).

The proprietary software's licensing must allow end users to reverse engineer it (section 6), and you have to provide the opportunity to re-link i.e. enable and allow the user to re-link the proprietary part against a modified version of the library.

(Usually this is done by using dynamic link libraries... or provide the object files for
 the proprietary part in the package and have linking done at installation time)

Sandra-24Author Commented:
Thanks for your help, I missed the catch in section 6. However, since most of the application is open source, including all the parts that interface with the 'library' it should be fine. Since no compiling is involved it is fairly easy to satisfy the requirements of the LGPL.

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