Re: [PATCH 0/5] [RFC] fixes for w32 and NetPBM

[Claudio Bley]

At Fri, 25 Oct 2013 21:45:19 +0300,
Eli Zaretskii wrote:
> 
> > From: address@hidden (Claudio Bley)
> > Date: Fri, 25 Oct 2013 17:35:18 +0200
> > 
> > Here are a few patches that have piled up in my local branch over the
> > last few months.
> 
> Thanks.
> 
> >   w32: define new jpeglib-version var in order to load the correct DLL
> >     at runtime
> 
> Are the newer DLLs binary incompatible with the older ones?  If not,
> I'd prefer not to introduce any version checking, since this increases
> the probability of the user's DLL being rejected by Emacs for no good
> reason.

Yes, it seems all releases since version 7 are incompatible with the
former ones.

> If there are indeed incompatibilities, can you point to the
> documentation that describes them?

I don't have a link to official documentation at hand (the jpeglib
website is a bit sparse), so I'm quoting wikipedia
(https://en.wikipedia.org/wiki/Jpeglib):

,----
| There are currently two conditions which trigger a major version bump
| of the JPEG library:
| 
| 1. New types of files can be created which are not compatible with prior 
releases, and
| 2. Changes in the master records which break the binary compatibility 
(usually addition of entries for new functions).
| 
| In all major upgrades since v6 both conditions 1. and 2. came
| together, while the source compatibility (API) could largely be
| retained.
`----

> >   w32: add support for default library names for libtiff
> 
> Where did you find these newer ports of libtiff?  Maybe we should
> amend the instructions in nt/INSTALL and nt/README.W32.

I'm using the latest officially released version from
http://www.remotesensing.org/libtiff/.

> >   Fix file magic for pbm files with comments
> 
> I don't think I've seen this part.  Did you send it?

Somehow this part didn't make it. I'll re-send.