NOTE: In what follows, IANAL, and I can't vouch for any specific constraints that may exist in legislation specific to your locale, but these are the general interpretations of the intent, AFAIK.
> I am wondering to know some details about FLTK licence. > the Graphics library FLTK is available under GPL licence with > some exceptions. It is derived from the LGPL, rather than the GPL, and that makes a difference. > 1/ I wonder to know if we can use FLTK to produce a > commercial product? Yes, it can. > 2/ If yes, have we to make the code source as open source? No, not as such. You need to make any changes you make to fltk itself freely available as open source, and you need to acknowledge your use of the fltk libraries in your code. Your application code itself need not be made open, unless you want to, of course. > 3/ "Static linking of applications and widgets to the > FLTK library does not constitute a derivative work" > what do they mean by this? This is specifically disclaiming one of the terms of the LGPL, with respect to what constitutes a "derivative work". Under the LGPL licences, "derivative works" must automatically be placed under the LGPL, and the wording is such that static linking to the library would constitute a "derivative work". The creators of the LGPL intended that you link dynamically to the library, so that the end user could, at their discretion, replace the version of the library with a later, or different, version. The idea being to give the end user more freedom of choice. So if you link statically, you must release the whole app under LGPL, but if you link dynamically you do not. Now, since fltk is designed with static linking in mind, that would obviously be an issue. So the fltk creators put in this clause stating that static linking does not constitute a derivative work in this specific case, and so the linked application need not be released under the LGPL for this reason. Note that this does not mean that the application is not subject to the LGPL clauses for other reasons, however, so you need to check all the cases, and all the libs that you are calling or linking against to see what might apply. If you are *really serious* about this, you need to get a proper lawyer to tell you what this means in your specific jurisdiction - my opinion, or that of others here, will carry very little weight if it all ends up in court! (Though I doubt that it ever would, of course...) SELEX Galileo Ltd Registered Office: Sigma House, Christopher Martin Road, Basildon, Essex SS14 3EL A company registered in England & Wales. Company no. 02426132 ******************************************************************** This email and any attachments are confidential to the intended recipient and may also be privileged. If you are not the intended recipient please delete it from your system and notify the sender. You should not copy it or use it for any purpose nor disclose or distribute its contents to any other person. ******************************************************************** _______________________________________________ fltk mailing list [email protected] http://lists.easysw.com/mailman/listinfo/fltk
