Re: libtool--gary--1.0--patch-25

[Gary V. Vaughan]

Bob Friesenhahn wrote:
> On Wed, 7 Jul 2004, Gary V. Vaughan wrote:
> 
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>> Okay to apply?
>>
>> I ask because, even though it fixes an obvious bug, it breaks
>> binary compatibility with libtool-1.5.x libltdl.  I think the
>> change only breaks loaders compatibility, and I believe there
>> are not yet any 3rd party loader.
> 
> 
> Does anything outside of libltdl ever copy or take sizeof() lt_dlinfo?
> If not, then the change does not seem significant and it should be safe
> to commit.

That is not how the interface is supposed to be used, though there is
nothing stopping an application from doing that.  Even then, copying
an oldsized chunk of the new struct and only referencing the old fields
is safe enough...  it would only be a problem if it had shrunk, no?

> If actual binary compatability is impacted (i.e. compiled applications
> stop working), then it can be tricky to get the library versioning
> correct so that both the head version and the release branch can safely
> coexist on a system.  Blindly following libtool's library revisioning
> rules for head and release branch can get you into trouble.

Hmm... hadn't thought of that :-(  I'm going to hit exactly that issue
with my next couple of patch proposals too...

Any thoughts on how to manage it?  I suppose we could reserve a block
of unused interface numbers (the next 20 should be sufficient) for a
release branch when we make our first alpha from HEAD.  Or am I over-
simplifying?

I was thinking that we should perhaps keep a separate tally of interface
changes that we can consult when making a release to help decide on
appropriate -version-info paramaters.

Cheers,
        Gary.
-- 
Gary V. Vaughan      ())_.  address@hidden,gnu.org}
Research Scientist   ( '/   http://tkd.kicks-ass.net
GNU Hacker           / )=   http://www.gnu.org/software/libtool
Technical Author   `(_~)_   http://sources.redhat.com/autobook

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