[geos-devel] [postgis-devel] GEOS C++ API deprecated?

Sandro Santilli strk at kbt.io
Wed Oct 4 00:29:04 PDT 2017

On Tue, Oct 03, 2017 at 08:15:05PM -0400, Greg Troxel wrote:

>   3) do I reimport the geos package as geos35 and namespace it to allow
>   simultaneous installation with the 3.6 version, and have some way for
>   osm2pgsql to link against the 3.5 version instead.

The C++ geos library should already have a different name for every
version (both filename and SONAME). But I guess you'd need to tweak
the link line of depending packages to find the correct one ?

>    Is it a geos bug that the C++ API changes in ways that break programs
>    that use it?

I wouldn't say so. It's documented that the C++ API is subject
to frequent changes. In the future I see more smart pointers and
templates coming, which would be again destruptive for the C++ API
(but safe for the C API).

>    Is it a bug for other programs to use the C++ API at all?

It's not a bug per-se, but it introduces some issues for

>   programs shouldn't really use the C++ API.  But if they do, they have
>   to cope with changes, because we aren't making stability guarantees.
>   So packagers should feel free to update geos to a release with an
>   API-breaking change after a few months, and if any depending package
>   breaks, it's their fault because they should have had a new release
>   that can use the new API.

Had you consider NOT replacing one version of GEOS C++ library with
another but rather keep both, when one of the packages doesn't build
(or work, ABI-wise) with new version ?


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