GPL license question

[lucasart]

I have created different pgn tools and sometimes these were distributed to other interested people.

Some of these tools uses the python-chess modules. Note that python-chess is under GPL3 license.

https://pypi.python.org/pypi/python-chess

Basically I install python and python-chess in my windows OS PC. I can then create scripts using python-chess by adding it at the top of the script,

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import chess
from chess import pgn
from chess import polyglot

I also convert the python scripts to exe file for windows using py2exe, for those people who are just interested in the exe file.

My question is, am I required to license (GPL3 for example) my pgn tools because I am using python-script modules in it? Or it is enough to distribute the source of my script, acknowledge the author of python-chess and include the source of pyhon-chess in the distribution although it is downloadable at the author's site?

Generally I don't like adding licenses to these little pgn tools.

So long as you don't include python-chess with your program, you don't need a GPL.
* If you distribute your program as Python source only, and don't include python-chess sources with it, you are free to choose whatever license you want (even no license)
* If you distribute your program as Python source only, and you include python-chess sources with it, you must use the same GPL v3.
* If you distribute your program as a compiled executable, the python-chess source code is effectively combined with it, so you must use the same GPL v3.

Thanks for the input.
Let me clarify on the first point.

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* If you distribute your program as Python source only, and don't include python-chess sources with it, you are free to choose whatever license you want (even no license)

So if I will just use python-chess modules in my code via

Code: Select all

import chess 
from chess import pgn 
from chess import polyglot

I am not required to add a license to my code?

That's correct.

Imagine if all C programs had to be GPL, because they were dynamically linked against glibc

[Evert]

Imagine if all C programs had to be GPL, because they were dynamically linked against glibc

Bad example. Glibc is LGPL, which indeed allows dynamic linking without infecting the linked software with its own licence. Contrast readline, which is GPL.

[syzygy]

Imagine if all C programs had to be GPL, because they were dynamically linked against glibc

Bad example. Glibc is LGPL, which indeed allows dynamic linking without infecting the linked software with its own licence. Contrast readline, which is GPL.

The FSF would very much like to have copyright on their side on this issue, but it is legally untenable to argue that the copyright on glibc extends to a program dynamically linking to glibc.

Even if glibc were GPL or under a very restrictive commercial license, you can't infringe the copyright on it by distributing source code that does not have glibc's code in it or object code that does not have glibc's code in it. A binary that dynamically links to glibc does not have glibc's code in it.

Things might be different if you're distributing a binary dynamically linking to glibc together with glibc. Even then I would tend to see the two as separate "works" in the sense of copyright.