There''s a rather large important distinction between GPL and LGPL -- which license does the library use? (Most libraries tend to use LGPL but some do use GPL -- beware!).

Anyway, if you include an LGPL library binary (ie. a DLL) in your distribution you must include the copyright/license terms in the distribution (in a README, or whatever) and you must also make the source code of the library available upon request..Even if you haven''t changed it (if you have changed it you must make your changes available).

What this means is if someone using your software requests the source to the the LGPL library you must put it up on a website or mail it to them on CD (charging them a nominal shipping charge to cover the S&H and materials) or provide some means of giving them the source -- note that giving them a link to the original project source or some mirror that you dont own doesn''t legally constitute giving them a copy; but in practice virtually all people will just go get it from the main site if you offer to send them a CD in a month for $8 if they want, but also include the link in your (e)mail back to them. So the practical effort required to deal with these license terms is virtually non-existent because people never request the source code anyway, particularly if you haven''t made any significant changes.


HOWEVER, if the library you use is GPL, then your whole program MUST be released under the GPL. Even if you write a 100,000 line game and link it to a 100 line GPL library, you must release the whole project as GPL if you distribute the binaries at all. What this means is anyone you distribute the binary to can request the source to your entire project (and then they can go and give it (the source) to anyone else they want to, because the GPL terms say so). According to the letter of the GPL you must honor all such requests. There''s a lot of debate as to whether or not the GPL is even legal (its never been really tested in court); but even if its not; you generally dont want to anger the GPL-zealots that will come down hard on you if you even seem to be violating the tiniest portion of the GPL.

In short, don''t link to a GPL unless you''re fully comfortable with your entire project being GPL itself. However, feel free to use LGPL libraries, just follow the simple rules.

umm actually under the terms of gpl ONLY ppl who have access to the excutable LEGALLY have access to the source. furthermore, you CANT just distribute an exe you paid for, and it DEFINATLY will not cover the art, sounds, movies, etc. only the excutable code. which means the following:

if a game is released as a commercial endeavor. only ppl who purchase the game legally from an authorized retailer can use the game. therefore they are the ONLY ppl who have access to the source code.

now the problem is MANY open source advocats feel that once its GPL its fair game for anyone to have the source, executable, art, etc that make the app tick. its just not so, though you will have much open and blantant piracy of your game. i HIGHLY suggest staying away from ANY GPL code.

LGPL is safer because it only requires a mention and as said a method to update (ie via dlls is best). also less ppl are going to blantantly pirate your game (since they dont have the source to the game, they feel less inclined that they can freely distribute things they dont own the rights to).

ppl obviusly dont understand the fine subtlties that allow GPL to be a commercially viable solution. personally, i dont get involved in GPL projects unless they will remain purly free (in price AND source). since if a commercial entity decides to use my source and make money, i want a piece of the action. this is why its best for GPL users to include such clauses (ie not for commercial use).

quote:Original post by a person
umm actually under the terms of gpl ONLY ppl who have access to the excutable LEGALLY have access to the source. furthermore, you CANT just distribute an exe you paid for, and it DEFINATLY will not cover the art, sounds, movies, etc. only the excutable code. which means the following:

Agreed. You can however compile the source and distribute the resulting binary and source.

quote:
if a game is released as a commercial endeavor. only ppl who purchase the game legally from an authorized retailer can use the game. therefore they are the ONLY ppl who have access to the source code.

But once you have the source code -- and the GPL states than anyone using the binary code must have access to the source -- you are allowed to modify it, redistribute it, etc. It means than it is perfectly legal to redistribute and/or modify the source. It is not legal, however, to modify, redistribute, etc. the artwork and the such. Basically, anyone can have your source code if you distribute your application, and that''s the whole point behind the GPL.

quote:
now the problem is MANY open source advocats feel that once its GPL its fair game for anyone to have the source, executable, art, etc that make the app tick. its just not so, though you will have much open and blantant piracy of your game. i HIGHLY suggest staying away from ANY GPL code.

You probably haven''t met much ''open source advocates''. They tend to be much more respectful of copyrights than most people, even if they disagree with them. Again, the GPL specifies that, if you have the binary file, you must have an access to the code (the offer must stand at least 3 years). It is also perfectly legal to compile the code yourself and redistribute the newly made binary (without artwork, etc) and the source code (it actually happens quite often in the community where people contribute RPM, DEB, PKG, EXE and other binary formats for their OS of choice).

quote:
LGPL is safer because it only requires a mention and as said a method to update (ie via dlls is best). also less ppl are going to blantantly pirate your game (since they dont have the source to the game, they feel less inclined that they can freely distribute things they dont own the rights to).

You do know than 99.9999% of the "warez d00ds" out there don''t know what "source code" means, right? It''s not like giving away the source code will promote your application to the number one position on all the warez lists. And it''s not like not giving your source will prevent piracy either. There are thousand of commercial applications out there to prove this, and I don''t think you''ll find many free software application on warez either. People who use pirated software don''t do so in order to get the source code, they only care about the final product.

If you''re so unwilling to open your source, why use a free license at all in the first place? If you want to link against a GPL''ed library, however, you''ve got the obligation to distribute your source if you distribute your product. No rip-off allowed. I wonder why that bugs so many people, since proprietary software developers are supposed to be honest, unlike free software ones.

quote:
ppl obviusly dont understand the fine subtlties that allow GPL to be a commercially viable solution. personally, i dont get involved in GPL projects unless they will remain purly free (in price AND source). since if a commercial entity decides to use my source and make money, i want a piece of the action. this is why its best for GPL users to include such clauses (ie not for commercial use).

Which makes it non-GPL, AFAIK, as you''re restricting the rights of the user to reuse the code and/or redistribute it. If you''re the owner of the source (and use no other GPL code), you can always sell a proprietary license to a commercial entity anyway.

Finally, it is important to note than the LGPL isn''t really convenient for applications (as opposed to libraries), as it requires that you link dynamically. Doing so against an application being quite difficult, the LGPL is really suited for libraries only.