[geos-devel] NEWS comments

[Greg Troxel]

Sebastiaan Couwenberg <sebastic at xs4all.nl> writes:

> I don't think it's the job of a packaging system to specify which
> compiler features should be used for reverse dependencies. Stuff like
> pkg-config was invented for that.

The point is to document that a compiler capable of c++11 is required,
so that if the current compiler isn't new enough, one can be built and
used instead.

But I'm not trying to push one packaging system's view on the world,
just to ask that things be clear.


> ldd has misleading output, objdump is more reliable:
>
> $ ldd /usr/lib/libgdal.so.20.1.2 | grep geos
>         libgeos_c.so.1 => /usr/lib/x86_64-linux-gnu/libgeos_c.so.1
> (0x00007fa48c768000)
>         libgeos-3.5.1.so => /usr/lib/x86_64-linux-gnu/libgeos-3.5.1.so
> (0x00007fa47f809000)
>
> $ objdump -x /usr/lib/libgdal.so.20.1.2 | grep NEEDED | grep geos
>   NEEDED               libgeos_c.so.1
>
> GDAL should not be using the GEOS C++ API, see m4/geos.m4 in the GDAL
> source how it detects the library to link.

Thanks.  objdump -x shows libgeos as NEEDED, but configure found the C
API, and so far I haven't figured out where it's coming from - will keep
looking.

> In your case it seems that you need to tell pkgsrc that building geos
> with non-C++11 compilers is not possible.

Yes, it will be marked "USE_LANGUAGES+= c++11", which is normal for us.

> I do wonder why those users
> can get a compiler with C++11 support from pkgsrc though. It's just a
> dependency issue, if you want to build the new geos, you need to update
> your compiler to suitable version first.

Yes, but we have a notion of base system compiler and extra compiler
from pkgsrc, and thus the question is when the force the new one.

> Personally I also think that the file list requirements from pkgsrc are
> an unnecessary burden to packagers, causing them to request detailed
> changelog entries mentioning those file changes from upstreams. Debian
> packages automatically generate the list of files they include, and if
> you want to see the changes there are tools like debdiff.

There are pluses and minuses.  I only ask when I see API withdrawals not
mentioned.  Often it's an omission of documentation, but sometimes
things are broken.  Whether I change a file or just see a diff, it's the
same question.

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