[Discuss] GPL and code linkages

[blu at nedharvey.com (Edward Ned Harvey (blu))]

> From: discuss-bounces+blu=nedharvey.com at blu.org [mailto:discuss-
> bounces+blu=nedharvey.com at blu.org] On Behalf Of MBR
> 
> In traditional compiled code, linking object files together to form a
> single executable made them part of the same work, and if any object
> file was compiled from GPL'd source, then the source for all objects had
> to be under GPL-compatible licenses.  On the other hand, two separate
> executables can be distributed in a collection of code (e.g. on the same
> CD), and either one being GPL'd doesn't require the other one to be
> GPL'd.  

IANAL.
YNAL.

What you wrote above is commonly accepted, but not yet tested in court.  Which means it's all subject to interpretation.  To the extent that there is any wiggle room in the interpretation, you need a lawyer, but even then, the lawyer's interpretation isn't necessarily going to agree with any judge's or jury's interpretation.

To further the "you need a lawyer" with "you don't need a lawyer," you gotta ask yourself, in the event of somebody pressing charges against you, *who* would press the charges?  Either the FSF or the copyright owner of some supposedly infringed GPL code.  So if we're talking about drupal as the GPL'd code, look at your stuff and ask yourself if drupal would ever press charges against you.  I'm guessing not.  (Look at the copyright notices inside the drupal code, to see who actually owns it.  But I'm still guessing not.)  

The FSF has been known to press charges for GPL violations on behalf of some GPL projects that otherwise wouldn't have pressed charges (that's part of how FSF makes money.)  But those charges are for things like ... Embedding busybox into a router and not telling anyone there's any GPL code in there, not providing the source, etc.  This is the reason why nowadays manufacturers are hyper-careful to include license notifications and provide a download link for the GPL'd code they used in their product.

So, would the FSF press charges against you?  I'm guessing they only press charges in situations where there's a clear violation and money at stake.  Why would they want to drag something to court to clarify any of the ambiguously written, unclearly defined parts of the GPL that they wrote?  Why would they want to harm the open source community as a whole, and reduce the compatibility with non-open-source projects, by digging deeper and defining more precisely, what constitutes a "derived work?"


> Writing a PHP
> extension probably requires licensing the extension under a
> GPL-compatible license because the PHP interpreter itself is GPL'd.  

I don't interpret it that way.  Because your extension is stored in a completely separate file.  At no point did any GPL code get compiled or stored or derived into any other form and then stored in your file.  You're just interfacing their API.