SDL license for multiple SDL libs

SDL Development
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Le mercredi 9 Juin 2004 00:40, Ken Rogoway a ?crit :

We are using SDL, SDL_image, SDL_mixer and SDL_ttf. All of these are
supported in part by Sam (along with some other people). However, each one
has a license (README) file that we are suppose to distribute with our game
to comply with the LGPL. Each of these files is identical.

The fact that these libraries are licensed under the LGPL forces you to
release your program under the LGPL.

  • -> section 2. c “You must cause the whole of the work to be licensed at no
    charge to all third parties under the terms of this License.”

Major disclaimer: I am not a lawyer, and I don’t guarantee that I
haven’t misinterpreted or missed part of the license myself. That
said…

Section 2 seems to primarily apply to making direct derivatives of the
library itself. Observe Section 6:

  6. As an exception the Sections above, you may also combine or
link a "work that uses the Library" with the Library to produce a
work containing portions of the Library, and distribute that work
under terms of your choice, provided that the terms permit
modification of the work for the customer's own use and reverse
engineering for debugging such modifications.

  You must give prominent notice with each copy of the work that the
Library is used in it and that the Library and its use are covered by
this License.  You must supply a copy of this License.  If the work
during execution displays copyright notices, you must include the
copyright notice for the Library among them, as well as a reference
directing the user to the copy of this License.  Also, you must do one
of these things:

Five options are then offered, of which the first two are the most
significant: (a) make available the program source or
object code so it can be relinked with a modified version of the
library, as well as providing the source code to any modifications to the
library used in the work; and (b) dynamically link with the library rather
than statically linking, so that the library can be reasonably replaced by
the user. ©, (d), and (e) are just variations of (a) and (b).

This is the primary distinction between LGPL (permits linking with non-free
programs as long as the user can replace the library component) and GPL
(permits linking with free programs only).

The need for this is the essence of the LGPL : you can make tons of things
with the library, given that

  • the copyright holder is easy to find out
  • the license is readable without having to use another source of information
    than the source distribution
  • the changes made to the original version of the library are stated in clear
    notices
  • the licensing terms of the LGPL are preserved or replaced by the GPL

Again, this seems to be referring to derivatives significantly
consisting of the library itself, not merely other programs that are
linked with the library.

—> Drake WilsonOn Wed, Jun 09, 2004 at 10:15:08AM +0200, Michel Nolard wrote: