libjpeg vs. libjpeg-turbo

[Lawrence Velázquez]

On May 25, 2015, at 10:23 AM, René J.V. Bertin <rjvbertin at gmail.com> wrote:

> I did discover one obstacle to swapping libjpeg.8.dylib from port:jpeg and port:libjpeg-turbo: the former sets compatibility version 13.0.0, the latter version 9.0.0 . BTW, libjpeg.9.dylib has compat. version 11.0.0 ... so I'm not sure to what extent upstream really know what they're doing with OS X specific library versioning ...

Compatibility numbers are not compared across major library versions because client images use specific major libraries. You should not get into a situation where you are comparing libjpeg.8.dylib compat 13.0.0 and libjpeg.9.dylib compat 11.0.0.

> So if libjpeg is to be maintained as a 3rd alternative a patch will be required to change the compatibility and current version that is stored in libjpeg.8.dylib .

We should not roll back a library's compatibility number. Doing so presumes that the newer version is backwards-compatible with the older version.

It would make more sense to bring libjpeg-turbo up to compatibility version 13.0.0.

vq