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Comment by Jenk | Hacker News Reader

> Actually, under the GPL, this fact is immaterial. If the Winamp player contained any GPL code at all, modified or not, then it is a derivative work of that GPL code and anyone receiving a copy of Winamp is entitled to demand the full corresponding source be provided under a GPL license.

That's just not true, surely? Lest everyone using any flavour of Linux is liable to the same problem?

How many apps out there are using GPL code? Android, for example.

Making a derivative in the sense of adding functionality to it, I get, but using it as-is as a component or library surely doesn't - and cannot - fall foul of the license else the entire technosphere is liable.

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It is if you link it into your address space. If your code wants to be non-GPL then it needs to have some kind of barrier between it and the GPL code that it uses. For Linux, that would be the kernel syscall abi. But normally it's the process boundary. For example, if your program spawns the GNU gperf command, then its GPL license doesn't apply to your program. Furthermore, the generated code that the gperf command prints to stdout, is not encumbered by the GPL. In other words, the output of a GPL licensed program belongs to you. But if you were to copy gperf's .c files into your codebase and use their perfect hash table algorithm, then your software would become GPL encumbered, but only if you distribute. They will sue you and spare no quarter if you don't give your users the same freedoms that they gave you. Even if the gperf dev team doesn't do it, then some other org representing someone who contributed a bug fix once will. You can't hide and there is no time to survive, because GitHub can be easily monitored using tools like BigQuery.

> spare no quarter if you don't give your users the same freedoms that they gave you.

What? The actual history of GPL enforcement is restrained when it comes to remediation. Are you aware of some routinely punitive GPL enforcer that I am not? Or is this FUD or a joke?

I hope I've not missed some news about your own projects and that you've not been subject to anxiety or meanness on account of the GPL, either. :(

Yes, it's true. There's a reason GPL is called copyleft.

> Lest everyone using any flavour of Linux is liable to the same problem?

The kernel is GPL. applications running on it in usermode are not constrained by the license.

https://www.gnu.org/licenses/gpl-faq.en.html#PortProgramToGP...

You can have copyleft without virality; the Mozilla Public License 2.0 requires any modifications to a covered work to be released under the same license (copyleft), but does not extend this requirement to other code included in a combined work (virality). As I read the license, you could embed the Gecko browser engine in your proprietary e-reader software, and only your changes to the engine itself would have to be released as free software.

If you are linking against GPL code then yes it's true. If you are linking against LGPL code then it's fine. Note that running software on Linux doesn't mean you are linking to Linux. However, if you distribute Linux, then yes, you must supply the Linux source code on request.

The "technosphere" is generally fairly compliant on these things. There is no disaster. But this is also why most commercial companies avoid GPL libraries.

> Note that running software on Linux doesn't mean you are linking to Linux.

Technically, you do link to linux-vdso.so (or variants depending on architecture), which is part of the kernel image. There doesn't seem to be an explicit GPL exception for the sources of this library [0] but the general syscall exception [1] may or may not apply.

[0] e.g. https://github.com/torvalds/linux/blob/master/arch/x86/entry...

[1] https://github.com/torvalds/linux/blob/master/LICENSES/excep...

> That's just not true, surely?

It is true.

> Lest everyone using any flavour of Linux is liable to the same problem?

The Linux kernel has an explicit "system calls are not linking" exception to avoid any possible confusion on this matter.

https://github.com/torvalds/linux/blob/master/LICENSES/excep...

Merely using the kernel's facilities from user space does not make your program a derivative work of the kernel.

> Lest everyone using any flavour of Linux is liable to the same problem?

If by that you mean, if you are using Linux in production servers: You may use GPL software in a commercial setting. The source code part only applies if you are distributing software that contains GPL code.

> Android, for example

Yes, OEMs are expected to release their kernels' sources. Also yeah, they're mostly very bad at it.

The devil is in the Details. Usually a licence is applied to a single library or compilation unit.

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