Two facts:
- msgpack-c is licensed under the Apache 2.0 license at the time of writing.
- msgpack-c is also likely to be released as a header-only C++ library in a bit.
Now, at http://www.apache.org/licenses/LICENSE-2.0 (definition of "Derivative Works") the license states explicitly that code is not considered a Derivative Work if it's linked together or otherwise bound by name. However, header-only means that msgpack-c code will be directly compiled into the client code, without any linking or binding by name.
By any common reading of open source copyright law, this means that any code using the header-only msgpack-c will automatically be "infected" with the Apache license. That has a number of implications which might range from careless programmers unknowingly shipping their whole application under the Apache license, to careless programmers violating copyright law if they use msgpack-c in GPLv2 code.
Given that msgpack-c started out as a library meant for linked-in use, I wonder whether the Apache license is still a suitable license for this project, at least for the C++ part. If your intention is to allow client code to use msgpack-c without infecting them, then maybe a license that was specifically designed for header-only libraries would be more appropriate. The most prevalent of these licenses is probably the Boost license, http://www.boost.org/users/license.html although there might be others.
Please consider and if you decide to take action, gather the copyright holders to get agreement on this issue.
Thanks! Also, great software!
Two facts:
Now, at http://www.apache.org/licenses/LICENSE-2.0 (definition of "Derivative Works") the license states explicitly that code is not considered a Derivative Work if it's linked together or otherwise bound by name. However, header-only means that msgpack-c code will be directly compiled into the client code, without any linking or binding by name.
By any common reading of open source copyright law, this means that any code using the header-only msgpack-c will automatically be "infected" with the Apache license. That has a number of implications which might range from careless programmers unknowingly shipping their whole application under the Apache license, to careless programmers violating copyright law if they use msgpack-c in GPLv2 code.
Given that msgpack-c started out as a library meant for linked-in use, I wonder whether the Apache license is still a suitable license for this project, at least for the C++ part. If your intention is to allow client code to use msgpack-c without infecting them, then maybe a license that was specifically designed for header-only libraries would be more appropriate. The most prevalent of these licenses is probably the Boost license, http://www.boost.org/users/license.html although there might be others.
Please consider and if you decide to take action, gather the copyright holders to get agreement on this issue.
Thanks! Also, great software!