ExifTool Forum

ExifTool => Developers => Topic started by: peci1 on November 11, 2024, 12:33:46 PM

Title: ExifTool License in 2024
Post by: peci1 on November 11, 2024, 12:33:46 PM
On github, the LICENSE file only contains GPL, marking the repository as a GPL-licensed software.

However, the readme says exiftool is available under the Perl license.

What's correct? Or is it still dual license and I can choose whichever I like more? Ubuntu distributes exiftool as "Artistic or GPL-v1+". That would suggest the dual licensing is still correct.

Also, I have a question regarding the C++ API. As it is using exiftool through parsing the output of its binary, it should be safe to say that the GPL of exiftool doesn't need to be also on the C++ API, right?

Thanks for clarifications,
Martin
Title: Re: ExifTool License in 2024
Post by: Phil Harvey on November 11, 2024, 02:38:49 PM
Hi Martin,

It is a dual license.

The C++ API is not GPL.  I don't see why you think it needs to be.

- Phil
Title: Re: ExifTool License in 2024
Post by: peci1 on November 11, 2024, 06:08:04 PM
Thanks Phil. Maybe it would be reasonable to update the Readme to explicitly mention the dual licensing?

Regarding the C++ API - if you took exiftool as GPL, GPL is viral, so it needs all derivative works to be also GPL. Now, the inter-process boundary is often seen as a division line where this viral property stops. However, taking into account the fact that the C++ API is tightly coupled with the exiftool binary, I still see it as a gray zone because it is basically useless without the GPL'd binary. However, given that you are the maintainer of both, if you say it's no problem, then it's no problem :)

Thanks,
Martin
Title: Re: ExifTool License in 2024
Post by: Phil Harvey on November 11, 2024, 08:47:34 PM
The ExifTool README states this:

QuoteThis is free software; you can redistribute it and/or modify it under the
same terms as Perl itself.

and the Perl license says this:

Quote It is free software; you can redistribute it and/or modify it under the terms of either:

a) the GNU General Public License as published by the Free Software Foundation; either version 1, or (at your option) any later version, or

b) the "Artistic License".

I don't see the problem.

- Phil
Title: Re: ExifTool License in 2024
Post by: peci1 on November 11, 2024, 11:59:22 PM
Ah, right. I somehow made a connection that Perl license = Artistic only. If it covers both, then it's okay.

Thanks