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Comment by cel1ne | Hacker News Reader

AFAIK, you don't have to ship the source to be GPL-compliant, you just have to provide it upon request.

Nitpick: Not really. What you have to do is provide an offer for source code; accompanying the program, not after the fact. If anyone has not provided such an offer, they have already broken the GPL.

What does provide an offer mean in practice? A link or instructions somewhere?

“[…] a written offer, valid for at least three years and valid for as long as you offer spare parts or customer support for that product model, to give anyone who possesses the object code either (1) a copy of the Corresponding Source for all the software in the product that is covered by this License, on a durable physical medium customarily used for software interchange, for a price no more than your reasonable cost of physically performing this conveying of source, or (2) access to copy the Corresponding Source from a network server at no charge.”

— GPL 3, Section 6, alternative (b).

Yes, in GPL 3, a link would be enough, but the link must be already provided with the distributed program, you don’t get to only give the link only to those people who ask for it.

In GPL 2, a link is not OK, you must be prepared to send people the source code as “machine-readable copy”, “on a medium customarily used for software interchange”.

Also, the offer is open to any person. This is so that other people with copies of the program can fulfil their obligation by passing on the offer too. So maybe you make one GPL program specifically for Bill, you give it to Bill, and you write Bill the offer, never expecting him to care about the source code.

Six months later a teenager from a country you didn't know existed sends you an email - and the teenager would like source code please. They are legally entitled to that source code because of Bill's offer.

The written offer rule is deliberately the worst case. You should never choose GPL "written offer" with the expectation that this is reducing your work load or whatever, if you want least work just ship the source code with your program and fulfil the purpose of the GPL up front.

I believe the offer is for anyone you’ve distributed the program to. So if it was Bill who shared a copy of the program with the random teenager it would fall upon Bill to provide him with the source and not you.

Nope. The GPL expressly says "to give any third party". It's done this way on purpose.

my mistake. thank you for the correction.

The offer only has to be given to Bill, but the offer must be valid for anyone, including anyone Bill passes it on to.

That's fine, as long as the user rights are passed along.

GPL software can be used for any purpose, you just have to pass along the rights you were provided if you redistribute it.

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