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Date: Fri, 18 Mar 2005 14:43:13 -0500
From: David Schultz <das@FreeBSD.ORG>
To: Daniel Eischen <deischen@FreeBSD.ORG>
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Subject: Re: cvs commit: src/lib/msun/i387 fenv.c fenv.h
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On Fri, Mar 18, 2005, Daniel Eischen wrote:
> On Fri, 18 Mar 2005, Warner Losh wrote:
> 
> > > Yeah, well, that was your karmic punishment for touching the internals
> > > of FILE.  Serves you right!
> >
> > I didn't touch the internals of FILE.  I just helped clean up the
> > mess. :-(
> 
> That was me, but as I recall we ended up keeping binary compat
> by reusing an existing field and extending it (green's idea I
> believe).  I think the real pain came when we tried to fix
> the predefined stdio, stdin, and stderr descriptors to prevent
> ABI breakage for future FILE changes.
> 
> Has anyone experimented with symbol versioning yet?  I recall
> someone wanting to do that (dfr?).

I looked into it, but I don't have time to implement it.
Basically, 90% of the support is already there, and it would not
be hard to finish for someone who understands the rtld internals
already (I don't).  I successfully created a working versioned
math library by simply making a linker spec and passing the
--version-script option to ld.  All that's needed, I think, is to
teach the runtime linker to check the version fields.  Then we
just make a bunch of specs for the libraries we want to version.