[odb-users] undefined reference link error when use odm.dll

[Alessandro Catania]

I work on c++ code that use orm 2.3.0 on windows an gcc compiler.
Orm code is generated by odb and is a library (that I call orm.dll) and
contains polymorphism, in particular some destructors are defined pure
virtual in base class. Empty destructors are implemented in Cxx source.
Symbols are exported in my orm library as explained in manual in "16.2.2
Dynamic Loading of Database Support Code"

This library compile correctly, but when I use it in another part of code
linker give error undefined reference for destructors of base classes
(defined as virtual).
Could be that destructors symbols of base classes are not exported? But orm
should export all class and then also destructors.
Is there a working  example that put together polymorphism
https://git.codesynthesis.com/cgit/odb/odb-examples/tree/inheritance/polymorphism,
library and use of library?

Thanks and best regards,
Ale