Using SDL in Shareware and such

SDL Development
1

I am not sure if I understand the way LGPL works (or GPL for that matter). If I
write a game (for example) that uses SDL to display graphics, does that then
mean that I can not sell the game as shareware as it uses SDL and that I must
make the source for the game available?

2

Durandle, from all that ive heard, if you dynamicly link to SDL (ie you have
to give out the sdl dll(s) when you give out your program) you are free to
sell your program without making it open sourced.

if you staticly link SDL where the SDL code is part of your exe, you have to
give out the source code.

The reason for this doesnt have anything to do with money or copyright (i
dont think).

The reason is because SDL is open sourced, so the makers of SDL want it to
be changeable and updateable by anyone in anything that uses it.

If you dynamicly link your program to SDL, the user can change or update the
dll’s, thus maintaining the open sourced-ness of SDL.

If you staticly link SDL into your exe, the only way for users to be able to
change/update SDL is to be able to recompile your program, thats why it
requires you to make it open sourced in that case.

So, as long as you dynamicly link to SDL, you are free to do as you please
with your own program!

Pretty sure this is accurate, if it’s not please someone speak up.

Long live the new flesh!
Atrix> ----- Original Message -----

From: durandle@spymac.com (Durandle)
To:
Sent: Tuesday, February 03, 2004 6:35 AM
Subject: [SDL] Using SDL in Shareware and such…

I am not sure if I understand the way LGPL works (or GPL for that matter).
If I
write a game (for example) that uses SDL to display graphics, does that
then
mean that I can not sell the game as shareware as it uses SDL and that I
must
make the source for the game available?

SDL mailing list
SDL at libsdl.org
http://www.libsdl.org/mailman/listinfo/sdl

3

I am not sure if I understand the way LGPL works (or GPL for that matter). If I
write a game (for example) that uses SDL to display graphics, does that then
mean that I can not sell the game as shareware as it uses SDL and that I must
make the source for the game available?

As seen on the SDL home page:

“It is used by MPEG playback software, emulators, and many popular
games, including the award winning Linux port of ‘Civilization: Call
To Power.’”

Civ is a commercial game, if you hadn’t heard of it.

Also, under “Licensing” in the FAQ:

Q: Can I use SDL in a commercial application?
fine. You do not have to include the source code to your
application, since the end user can drop in a new version of the SDL
shared library, which is the intent of the license.

  Full details are available at: http://www.libsdl.org/license.php

Perhaps the “Licensing” page (linked-to from the sidebar) should
also link to the FAQ page?

-bill!
bill at newbreedsoftware.com "Hey Shatner, ya remember that episode of
http://newbreedsoftware.com/bill/ Space Trek where your show got cancelled?"On Tue, Feb 03, 2004 at 02:35:29PM +0000, Durandle wrote:
A: The simple answer is “Yes”, just dynamically link with SDL and you’re

4

I am not sure if I understand the way LGPL works (or GPL for that matter). If I
write a game (for example) that uses SDL to display graphics, does that then
mean that I can not sell the game as shareware as it uses SDL and that I must
make the source for the game available?

Nope, the rule with LGPL is that you have to give the end user the same
rights that you have. So, they have to be able to use their own version
of SDL with you game. There are two ways to do that, you can use .dlls
so the library is always dynamically linked with your program. Or, if
you want to statically link your game you must provide object files on
the web somewhere so that people can relink with their own version of
the SDL libraries. Most commercial games do it that way.

LGPL does not force you to provide people with the source code for your
game, ever.

OTOH, GPLed code forces you to provide source code. That is why most
people release libraries under LGPL and applications under GPL. They
want to keep the code they release public.

		Bob PendletonOn Tue, 2004-02-03 at 08:35, Durandle wrote:

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http://www.libsdl.org/mailman/listinfo/sdl
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±--------------------------------------+

5

“Alan Wolfe” wrote:

if you staticly link SDL where the SDL code is part of your exe, you
have to give out the source code.

as bob allready pointed out, this is not correct. providing the object
files for static linking fullfills the requirments of the LGPL.

clemens

6

interesting, didnt know that!

very cool tho, thanks> ----- Original Message -----

From: clemens@thf.ath.cx (Clemens Kirchgatterer)
To:
Sent: Wednesday, February 04, 2004 9:12 AM
Subject: Re: [SDL] Using SDL in Shareware and such…

“Alan Wolfe” <@atrix2> wrote:

if you staticly link SDL where the SDL code is part of your exe, you
have to give out the source code.

as bob allready pointed out, this is not correct. providing the object
files for static linking fullfills the requirments of the LGPL.

clemens

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