[zeromq-dev] Clarification of libzmq license

jamesniu jamesniu at pset.suntec.net
Fri Aug 22 03:57:52 CEST 2014


Hello Sir/Madam,

We are currently using ZeroMQ v3.2.2 for commercial applications’ development, 2 questions about license occurred during the development:
 
There is SLE in COPYING.LESSER of ZeroMQ v3.2.2, the exemption clause states as:
"As a special exception, copyright holders give you permission to link this library with independent modules to produce an executable, regardless of the license terms of these independent modules, and to copy and distribute the resulting executable under terms of your choice, provided that you also meet, for each linked independent module, the terms and conditions of the license of that module. An independent module is a module which is not derived from or based on this library. If you modify this library, you must extend this exception to your version of the library." 

As for ZeroMQ v4.0.4, there is a note added after the same exemption clause which states as:
 "Note: this exception relieves you of any obligations under sections 4 and 5 of this license, and section 6 of the GNU General Public License."

Could we comprehend that as:
Q1: Can this NOTE also apply to the SLE of ZeroMQ v3.2.2?
Q2: When we are using ZeroMQ v3.2.2, if we link libzmq, or a modified version of it, into an executable, also, we are exempt from the LGPLv3, as same as v4.0.4.

Look forward to any reply.

2014-08-22
James N.




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