Re: Lua and GNU readline linking

[Mike Pall <mikelu-0602@...>]

Hi,

Lefteris Chatzibarbas wrote:
> Lua 5.1 seems to link with GNU readline (when LUA_USE_READLINE is
> enabled).  IANAL, but I believe that this is a violation of the GPL
> license that GNU readline is published under, and Lua has to either
> change it's license to GPL [1], get a special permission from upstream
> authors/copyright holders, or stop linking with the GNU readline
> library.

Please do not spread FUD. The discussion is as old as this line
in the GPL FAQ. You can read about it in many mailing list
archives.

It's not the license that spreads, it's the license terms
("providing source code") that spread. And even this has been
debated at length, too. Consult a lawyer if you are in doubt.

Some things to consider:

- The Lua readline support depends on the readline API, but not
  on the readline library. It can be linked to libedit, too
  (BSD license).
  In fact precisely this happens on Mac OS X when one
  links with -lreadline (which is a symlink to libedit).

- Lua is only distributed in source form by the authors.
  And it's under a "GPL compatible" license.

- Anyone distributing a Lua binary linked to readline also
  provides the source (e.g. Debian or LuaBinaries).

- Embedded or console developers who are most likely to be
  affected by GPL license issues link the Lua core into their
  application. They are not using nor distributing the Lua
  standalone executable. They are not linking against readline.

Bye,
     Mike