[zeromq-dev] If we compile ZeroMQ sources without modifying them, and link the resulting DLL to an executable that is part of our commercial product , does this make our whole product become a software under LGPL license?

[Am Shalem, Shlomo [BWIIL]]

Thanks!

-----Original Message-----
From: zeromq-dev [mailto:zeromq-dev-bounces at lists.zeromq.org] On Behalf Of Luca Boccassi
Sent: Monday, November 13, 2017 12:19 PM
To: ZeroMQ development list <zeromq-dev at lists.zeromq.org>
Subject: [EXTERNAL] Re: [zeromq-dev] If we compile ZeroMQ sources without modifying them, and link the resulting DLL to an executable that is part of our commercial product , does this make our whole product become a software under LGPL license?

On Mon, 2017-11-13 at 06:48 +0000, Am Shalem, Shlomo [BWIIL] wrote:
> Hello
> 
> We are two people in our company, who are getting to opposite 
> conclusions, when reading the license and the license FAQ...
> Could you please help us with the doubt?
> 
> If we compile ZeroMQ sources without modifying them, and link the 
> resulting DLL to an executable that is part of  our  commercial 
> product ,
> 
>   1.  Does this make our whole product become a software under LGPL 
> license?
>   2.  OR does this maintain it as legal, closed-source software?
> 
> Thanks
> 
> Motivation: We are interested in compiling the sources because we are 
> using a late version of VisualStudio for which we did not find 
> compiled DLL in the ZeroMQ depository.

The short answers is the 2, the license of your code is not affected.

The verboser explanation is that any LGPL code can be dynamically linked to software of any license without affecting it. libzmq offers an additional grant of top of that which also allows statically linking.

https://github.com/zeromq/libzmq/blob/master/COPYING.LESSER#L169

--
Kind regards,
Luca Boccassi