I am close to releasing the first version of an open source program library that I have written, but I am finding it hard to select a proper license. Since I am not a lawyer and I have only a limited understanding open source licenses, I figured I would ask for recommendation.

The options I have considered are LGPL, MIT, and BSD license. The MIT and BSD licenses are almost identical and seem to offer the most freedom to users.

The most important requirement I have is that people can use this library with both closed and open source projects, proprietary or free software. To my understand, all the three options above fill this requirement.

What is your take on the licenses? Any reason to favor one over the other?

I'd appreciate all comments.

Yes, you are correct, all three of those would allow you to use your library in a proprietary program. The question is: What do want in return?

The MIT and BSD licenses greatest strength is also their greatest weakness. When you publish a work under one of these, you are granting almost absolute freedom to your code (with the exception that the copyright and the license is still included with your code). The downside is that there's very little legal coverage.

Ex: Let's say you make a simple program that calculates the area of a circle. You decide to release it under the BSD license because you don't want to deal with legal crap. (who does anyway?) Someone else comes along and says, "Hey, this is pretty good, I'm going to use this code in my proprietary program!" As long as they include the BSD license somewhere in their code along with your code, they could "leech" off the code and never let you know about it. If that person makes changes, they are not required to publish them.

Now the above example is rather silly and for what you plan on doing, the BSD or MIT license would serve you well. But what about the LGPL?

The LGPL is similar to the above except for one thing: all modifications and changes MUST be published. Therefore, if "Joe" wants to use your program in his proprietary program and makes changes to it, he has to publish the code that was changed (meaning not the whole program, but the one section that was changed). In this way, you are letting others use your code, but you can still track its progress and fix potential bugs that may occur.

Regardless, any of the three licenses mentioned will do the job for you. If I'm wrong, please point it out because I Am Not A Lawyer!

Thanks angryfirelord.

I must confess that I have not really thought about it from the angle, "what I want from the license". Personally, I would not mind knowing the progress of how and where my library is being used but mostly I worry about how commercial companies see it. I love open source and believe in it, but I also think open source should be compatible with business goals.

The LGPL is tempting but I am slightly worried about it. I took a read at it and the first thing that caught my eye was the section 2, C: "You must cause the whole of the work to be licensed at no charge to all third parties under the terms of this License". Does that mean that if someone uses my library, find a bug and fixes it for themselves, they must publish the update only or their entire product?

Also, what do you think about the LGPL 3? Should I give it a whirl?

I know you are not a lawyer, but bare with me

If my memory server me right, the GPL and LGP are basically the same, except that the LGPL allows proprietary software to link to it, and the GPL doesn't.

You probably want to consult this page for some quick info:
http://www.gnu.org/licenses/gpl-faq.html

I too I am not a lawyer....I am also not burdened by actually having read any of the licenses....

If I am not mistaken, the typical open-source license covers only the work that is under the license. At least in GPL, a central principle is that "what comes to you open must stay open". I am not aware of any license that would require sharing proprietary code because the end product incorporated some open-source elements.

Yeah, it's not easy reading it, but if you look below it, it states:
So in this chase, "whole" seems to refer to the modified work. Basically, the LGPL states that if someone modifies your library, they can't try to sell back the modification or fix. It must be published freely.

Not sure of the LPGLv3, but it is shorter than 2.1. Wouldn't hurt to look at it.

Same here but that is also the contradiction that I experience when I write open source code. Without reading (and also understanding it ) the licenses I only have the word of various sources (of equally various creditability) of how these licenses work.

So choosing the license for me is not an easy task.

Hehe... May I be the first person here to say right here and now, that I officially hate legal text

But yeah, it seems to make sense. Essentially anyone can link my library to their proprietary program but my library still stays open and licensed under LGPL. Also if the library is modified, it must be made available under the LGPL. The biggest difference between MIT/New BSD and LGPL is that software licensed under the later cannot be re-licensed under a different license (at least I hope that's how it works).

Naturally if the program is used privately and not distributed in any form, then it does not matter.

I thought about LGPL v3 and while it is shorter, what I understood from it, it is actually derived from GPL v3. So one should understand GPL v3 before he can understand LGPL v3.

Maybe, for simplicity's sake, I will stick with v2...

Of course if anyone here has first-hand understanding of the differences between v3 and v2 I am all ears.

My understanding is the GPL is doing precisely that; i.e. incorporating (linking) GPL code into proprietary code implies that the proprietary code has to be relicensed to the GPL.

This of course doesn't apply to the LGPL.

Well... you could also use both.

This way you can leave your original code under a BSD-Style license, allowing everyone to steal and abuse it while doing all your personal coding under a more protected GPL license

i would go for LGPL V2
if someone writes a propiratry prog using your lib then fine, they just have to give the source of your lib

if somone modifies your lib and writes a propiratry prog using the new lib, the new lib has to be LGPL but in both cases the propiratry prog is unnaffected

In the following reply, I'm going to assume for simplicity that you reside in the United States... (And: "I'm Not A Lawyer" ... I have a lawyer for that ... but I do own three copyrights which pay for the roof over my head...)

First, you need to officially secure your ownership of the original work. Copyrights are administered by the Library of Congress, so first you need to go here: http://www.loc.gov/copyright
and carefully read what it says.

It will cost you a grand total of $35(USD) to electronically(!) file "the necessary paperwork" and secure your copyright. Or $45.00 by snail-mail, which an old-fashioned luddite like me still prefers. Send the paperwork by registered mail, return receipt requested, since this receipt will provide legal proof of the date of your application. With this little formality out of the way, you have legally established that you own this work.

What You choose to do with "Your Property" is really up to You. (Capitalized "You" because "You are the God of Your Own Kingdom." This is "Your Baby: Make Of It What You Can.")

That is what "[the] copy right" means: after legally establishing that you created this work, you have the right to determine how your work may be used by others. This constitutionally-established right is ferociously protected.

If You find one of the published license-agreements suits Your sovereign fancy, then You are free to use their legalese and to deploy Your Baby under those terms. This does not remove Your right to change Your mind in the future.

If You do elect to distribute Your work with source-code and (the two are not related...) to not only permit but encourage the development of "derivative works" based on Your Baby, then You probably must choose one of the established, legally tested license-agreements under which to do it, because absent this, probably no one in their right mind will touch Your Baby for fear of Your Wrath... which under copyright law is actually quite terrible.

But the bottom line is, once You have legally registered Your copyright, the choice is Yours and the full power of the legal system is behind You.

Although the law does provide some provision for unregistered copyrights, $35.00 (USD) is a cheap price to pay. Do not neglect the paperwork, because you cannot meaningfully license what you have not first clearly and legally established that you actually own.

I came to the same conclusion yesterday. As far as I can tell, LGPL does a good job of protecting both my rights and also ensuring that my library stays opens.

I can happily report that I do not live in the United States. Here in Finland, copyright is acquired automatically for any literal or artistic work. Computer programs count as "literal" works. And the copyright exists until 70 years after my death, unless I resign or transfer the right to another person or persons in a written document (such as a testament). No registering is necessary.

So no worries

Thanks for the advice advice guys. Was really helpful

In the United States (as of January 1, 1978), copyright is also acquired automatically upon creation of a work. So no registration is necessary per se. If you happen to get into legal action (either on the giving or receiving end), the paperwork from registration will help greatly. For example, you cannot file an infringement suit without registering, and if you have your copyright registered quickly after creating the work and sufficiently before someone infringes the work, you may sue for statutory damages as well as the damages from the infringement itself.