iOS license revised...may allow dynamic linking?

Hi all,
Apple loosened the terms on their license agreement today. I think it
may allow for dynamic linking now (which has implications for using
SDL).
I do a short analysis about it here:

http://playcontrol.net/ewing/jibberjabber/apple-ios-license-term-chan.html

-Eric–
Beginning iPhone Games Development
http://playcontrol.net/iphonegamebook/

And its mainstream news now too.

Too bad this is after the Apple/Adobe squabble. Sure makes it seem shallow now.

At least all the libraries/interpreters developers have been using for
years are no longer in the same category as “sub-standard” app. I
guess competition really can be a good thing. Finally, Apple’s desire
to sell product is more than their need for absolute control.On Thu, Sep 9, 2010 at 2:01 PM, Eric Wing wrote:

Hi all,
Apple loosened the terms on their license agreement today. I think it
may allow for dynamic linking now (which has implications for using
SDL).
I do a short analysis about it here:

http://playcontrol.net/ewing/jibberjabber/apple-ios-license-term-chan.html

-Eric

Beginning iPhone Games Development
http://playcontrol.net/iphonegamebook/


SDL mailing list
SDL at lists.libsdl.org
http://lists.libsdl.org/listinfo.cgi/sdl-libsdl.org

It was already mainstream news when I posted, but the mainstream is
mostly focused on Flash. I wanted to bring attention these other
issues which have direct implications for SDL and may actually be far
more reaching than the focus on Flash. (There is a lot of (L)GPL
software out there.)

-EricOn 9/9/10, Jeremiah wrote:

And its mainstream news now too.


Beginning iPhone Games Development
http://playcontrol.net/iphonegamebook/

I wonder whats going to be the first app to advantage of this new,
more relaxed clause and what library it’ll use.(could it be SDL?) If
pygame gets ported, I would get an iphone/itouch just for that. Forget
flash.

P.S.
Maybe its time to put a yellow check mark next to iPhone and iPod
Development in the LGPL section of the table on the Galaxy GameWorks
page.On Thu, Sep 9, 2010 at 5:07 PM, Eric Wing wrote:

On 9/9/10, Jeremiah <@Jeremiah> wrote:

And its mainstream news now too.

It was already mainstream news when I posted, but the mainstream is
mostly focused on Flash. I wanted to bring attention these other
issues which have direct implications for SDL and may actually be far
more reaching than the focus on Flash. (There is a lot of (L)GPL
software out there.)

-Eric

Beginning iPhone Games Development
http://playcontrol.net/iphonegamebook/


SDL mailing list
SDL at lists.libsdl.org
http://lists.libsdl.org/listinfo.cgi/sdl-libsdl.org

P.S.
Maybe its time to put a yellow check mark next to iPhone and iPod
Development in the LGPL section of the table on the Galaxy GameWorks
page.

Well, we have a few things to do before that happens. First, we have
to figure out if/how to actually build a dynamic library on iOS. While
dynamic linking should be indeed possible (since all of Apple’s
frameworks must be linked to dynamically), the Xcode tool chain
disabled all the easy ways to build a dynamic library on iOS. We’ll
have to figure out if this is possible or hope Apple fixes Xcode.

(And this presumes my interpretation of dynamic linking is actually
allowed. I’m curious what others think which is why I posted in the
first place.)

-Eric–
Beginning iPhone Games Development
http://playcontrol.net/iphonegamebook/

P.S.
Maybe its time to put a yellow check mark next to iPhone and iPod
Development in the LGPL section of the table on the Galaxy GameWorks
page.
Well, we have a few things to do before that happens. First, we have
to figure out if/how to actually build a dynamic library on iOS. While
dynamic linking should be indeed possible (since all of Apple’s
frameworks must be linked to dynamically), the Xcode tool chain
disabled all the easy ways to build a dynamic library on iOS. We’ll
have to figure out if this is possible or hope Apple fixes Xcode.
My definition of dynamic linking is the act of loading and linking code
into your running process. In other words, linking at runtime instead of
compile time.

I know nothing about the iPhone processor and Xcode, but I did a kernel
for the Cell’s SPUs that would load code via DMA into the SPU local
storage, resolve any relocations and imports, and call the code’s entry
point. It’s based on GNU’s objdump and is not pretty… Basically:

  1. Compile the code with gcc to generate an object file
  2. Use objdump on the object file to get the generated code,
    relocations, imports and exports
  3. Write a file with that information using a custom format (in other
    words, create your own DLL-like file)
  4. At runtime, load the file generated at step 3, resolve all
    relocations and imports, get the exports your application wants to call

But then you have dynamic code which wants to call functions in another
library, i.e. SDL_ttf calling functions from both Free Type and SDL.
These functions will appear as imports in the object file so by
carefully ordering the files you load at step 4 one could load the
library with no imports from other libraries, than the libraries with
imports only from the libraries already loaded and so on until the last
library is loaded. So if you make a graph where the nodes are the
libraries and the edges mean “uses functions from”, you can load
libraries in the inverse order of a topological sort on the graph.

In theory…

Cheers,

AndreOn 09/09/2010 19:11, Eric Wing wrote:

(And this presumes my interpretation of dynamic linking is actually
allowed. I’m curious what others think which is why I posted in the
first place.)

-Eric

well let’s hope flash remains out of reach from iphone :slight_smile:
however about the (L)GPL software, if i understand it correctly, you
can statically link lgpl software as long as you provide the sources
of the software, isn’t it?
So this clause will indeed allow other toolchains to be available, but
i don’t really see a market increase for sdl (and sdl-like tools).
Please correct me if i’m wrong.

VittorioOn Thu, Sep 9, 2010 at 11:07 PM, Eric Wing wrote:

On 9/9/10, Jeremiah wrote:

And its mainstream news now too.

It was already mainstream news when I posted, but the mainstream is
mostly focused on Flash. I wanted to bring attention these other
issues which have direct implications for SDL and may actually be far
more reaching than the focus on Flash. (There is a lot of (L)GPL
software out there.)

-Eric

Beginning iPhone Games Development
http://playcontrol.net/iphonegamebook/


SDL mailing list
SDL at lists.libsdl.org
http://lists.libsdl.org/listinfo.cgi/sdl-libsdl.org

well let’s hope flash remains out of reach from iphone :slight_smile:
however about the (L)GPL software, if i understand it correctly, you
can statically link lgpl software as long as you provide the sources
of the software, isn’t it?
If you statically link to LGPL’ed software you have to provide the users
of your software the ability to update it to use the latest version of
the LGPL’ed software. You can do this by providing source code, so that
they can rebuild your software, or the object files, so that they can
relink them.On 12/09/2010 11:32, Vittorio G. wrote:
So this clause will indeed allow other toolchains to be available, but
i don’t really see a market increase for sdl (and sdl-like tools).
Please correct me if i’m wrong.

Vittorio

On Thu, Sep 9, 2010 at 11:07 PM, Eric Wing wrote:

On 9/9/10, Jeremiah wrote:

And its mainstream news now too.
It was already mainstream news when I posted, but the mainstream is
mostly focused on Flash. I wanted to bring attention these other
issues which have direct implications for SDL and may actually be far
more reaching than the focus on Flash. (There is a lot of (L)GPL
software out there.)

-Eric

Beginning iPhone Games Development
http://playcontrol.net/iphonegamebook/


SDL mailing list
SDL at lists.libsdl.org
http://lists.libsdl.org/listinfo.cgi/sdl-libsdl.org


SDL mailing list
SDL at lists.libsdl.org
http://lists.libsdl.org/listinfo.cgi/sdl-libsdl.org

Hi, is anyone working on SDL dynamic linking for iOS?

I played with it, but as far as I can tell, it will require Apple
support to de-cripple things. I posted a couple quick updates here:
http://playcontrol.net/ewing/jibberjabber/apple-ios-license-term-chan.html

All I can say now is file a bug report with Apple and get others to do the same.

-EricOn 10/25/10, kanguru007 wrote:

Hi, is anyone working on SDL dynamic linking for iOS?


Beginning iPhone Games Development
http://playcontrol.net/iphonegamebook/