[postgis-users] PostGIS and GEOS on FreeBSD 4.11: problem with libstdc++.so.6

[Markus Schaber]

Hi, Toomas,

Toomas Aas wrote:

> ERROR:  could not load library
> "/usr/local/lib/postgresql/liblwgeom.so.1": dlopen
> (/usr/local/lib/postgresql/liblwgeom.so.1) failed: Shared object
> "libstdc++.so.6" not found, required by "libgeos_c.so.1"
> CONTEXT:  SQL function "geomfromtext" statement 1
> 
> The problem with this message is that all these library files actually
> do exist and are listed in output of 'ldconfig -r', so I don't
> understand why libstdc++.so.6 can't be found. Does this qualify as a
> "weird problem (backend unexpectedly closed or similar thing)",
> indicating that I need to rebuild PostgreSQL?

I think this qualifies as a variation of that "weird problem".

> To make life even more interesting, building GEOS on FreeBSD 4.11 pulled
> in GCC 3.4 as a dependency and used that to compile itself, whereas
> PostgreSQL and PostGIS got built with GCC 2.95, which is standard in
> FreeBSD 4. So I actually have two versions of lstdc++:
> /usr/lib/libstdc++.so.3
> and
> /usr/local/lib/gcc/i386-portbld-freebsd4.11/3.4.6/libstdc++.so.6

That seems to be the problem - you pulled the dependencies of two
different libstdc++ versions.

And, AFAICT, GCC 2.95 was one of the old versions that exposed the bug,
3.4 has (at least on Linux) fixed it.

> I wonder if I should perhaps try to build PostgreSQL and PostGIS with
> GCC 3.4, so they all use the same C++ libraries?

Yes, that seems to be the solution.

Additionally, AFAICT, GCC 3.4 and 2.95 have different binary interfaces
for C++, leading to anything from linkage errors over crashing
applications to production of fake data.

HTH,
Markus

-- 
Markus Schaber | Logical Tracking&Tracing International AG
Dipl. Inf.     | Software Development GIS

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