[postgis-devel] liblwgeom symbols exported by postgis

[Sebastiaan Couwenberg]

On 29-09-15 09:25, Sandro Santilli wrote:
> On Tue, Sep 29, 2015 at 08:50:21AM +0200, Sebastiaan Couwenberg wrote:
> 
>> Debian will keep dynamically linking liblwgeom whether the upstream
>> developers agree or not. We only want to fix security issues and other
>> bugs in a single library, not in everything that embeds a copy (by
>> included a copy of the source or static linking).
> 
> Just to gather more information about this,
> would it be possible to install both PostGIS 2.0 and 2.1 on the same
> system via debian packages ? If so, would them be usable on the
> same database (different schemas) ?

In theory the postgis packages for 2.0 & 2.1 are co-installable because
the package name includes the version. Whether this actually works in
practice I cannot say, maybe Markus has experience with such a setup?

The Debian repositories only supply a single postgis version, so you'd
need to build 2.0 manually.

>> I'm no expert on linking issues, so I don't have good advice for Reginas
>> issue. But not exporting another libraries symbols should be common
>> sense, GDAL exporting the lib(geo)tiff symbols when the embedded copy is
>> used caused all kinds of problems requiring the need to rename those
>> symbols for example.
> 
> Is this any different from mixing dynamic linkage of different SONAME'd
> libraries having the same symbol names into the same binary ?

Linking-wise it shouldn't be any different, there a multiple library
exporting the same symbols. This should be like Highlander: There can be
only one. ;)

Kind Regards,

Bas

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