ABI Compatibility (was Re: Installation woes for the average user...)

[Gregory Casamento]

The last collective release was only two months ago.

As far as the ABI is concerned that is certainly an issue.   The last time we discussed it we came up with two solutions:

• Pad the ivar-structures in the classes out to give space to grow so that it pushes off any ABI compatibility issues as long as possible.   This is why in some APIs, including Cocoa, you see things like "reserved..." or "private..." variables.  These are there to give room to grow.  The disadvantage is that the classes would then take up more memory as a result.
  
• Move the ivar-structures out of the classes and replace them with a void pointer to the actual structure.   This has the advantage that we will never be able to break ABI compatibilty since the sizes of the structs in the classes will not change... but it also has the disadvantage of adding a layer of complexity to getting and setting variables as well as potentially causing unpredictable issues due to unforseen incompatibilities such as cases where the wrong data is written into a data structure causing some sort of corruption when using the wrong version of a library.

I, personally, think we should implement the first option.  It's
the method most APIs follow and it is the method that is the most
predictable.  It would take some effort to do this, but it's minimal
since it's really just padding the structures with a given amount of
space.   

GC
P.S. Sorry for the double mail, Stefan, I meant to reply to all, but curse gmail it defaults to reply. :)

On Thu, Mar 5, 2009 at 8:35 AM, Stefan Bidigaray <address@hidden> wrote:

I thought that's what GNUstep-startup was supposed to be used for?  I've personally never used it, but the way I understand it all you need to do is "./InstallGNUstep", right?

 

In my opinion, it's more important to have up-to-date packages than anything else, however, one needs to keep in mind that most distributions do not follow the latest and greatest.  I, for example, use Debian Testing + GNOME most of the time and I know I will never have the latest release of packages, people need to realize this.  Tell you the truth, except for when I create GNUstep packages and build scripts for Slackware, I never compile a single piece of software.  Why is it different with GNUstep?  Why do people WANT to compile in the first place?

 

If I can rant a little... GNUstep also gets way behind when it comes to releases.  How long has it been since the last collective release?  Why isn't GNUstep releasing more stable releases?  It seems everytime a new release of the core packages are out I need to recompile everything because it breaks ABI.  Rarely do I see a x.x.1 release.

 

I've been wanting to bring that up for a while, figured this was as a good a time as any.

 

Stefan

On Wed, Mar 4, 2009 at 10:33 PM, Gregory Casamento <address@hidden> wrote:

Hey guys...  it seems to me that the build guides for building from source that we have are out of date.   Could we move  some of this stuff to the wiki so that it can be more readily maintained?

Also, it seems like a lot of users are having issues using GNUstep because the packages are so old on many systems.  Currently Hubert is working on

What brought this up is that I was trying to help someone get gnustep installed since the packages are out of date.

Anyone have any thoughts?
GC
--
Gregory Casamento
Open Logic Corporation, Principal Consultant
## GNUstep Chief Maintainer
yahoo/skype: greg_casamento, aol: gjcasa
(240)274-9630 (Cell), (301)362-9640 (Home)

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-- 
Gregory Casamento
Open Logic Corporation, Principal Consultant
## GNUstep Chief Maintainer
yahoo/skype: greg_casamento, aol: gjcasa
(240)274-9630 (Cell), (301)362-9640 (Home)