ExifTool License in 2024

[peci1]

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

[Phil Harvey]

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

[peci1]

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

[Phil Harvey]

The ExifTool README states this:

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

and the Perl license says this:

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

[peci1]

Ah, right. I somehow made a connection that Perl license = Artistic only. If it covers both, then it's okay.

Thanks