Unable to load shared object with inherited class in a R package - rcpp

Question

I am creating a R package using Rcpp. In this package, I want to create classes that will not be exported to R, with a class inheriting from another.
I created a package with Rcpp.package.skeleton(), to which I added two files in the src directory.
I have a file A.h:
class A {
public:
virtual ~A();
};
class B : public A {
public:
B();
};
And a file A.cpp:
#include "A.h"
B::B() { }
When compiling the package, I get the following error:
Error in dyn.load(dllfile) :
unable to load shared object '.../test/src/test.so':
.../test/src/test.so: undefined symbol: _ZTI1A
I only find resources about exposing such classes to R, but I am wondering whether it would be possible to use such a class internally, without exposing it to R?
Edit: If I understand correctly, the files necessary for building the package are:
NAMESPACE:
useDynLib(test, .registration=TRUE)
exportPattern("^[[:alpha:]]+")
importFrom(Rcpp, evalCpp)
DESCRIPTION:
Package: test
Type: Package
Title: What the Package Does in One 'Title Case' Line
Version: 1.0
Date: 2020-06-23
Author: Your Name
Maintainer: Your Name <your#email.com>
Description: One paragraph description of what the package does as one
or more full sentences.
License: GPL (>= 2)
Imports: Rcpp (>= 1.0.4)
LinkingTo: Rcpp
RoxygenNote: 7.1.0

Answer 1

This has nothing to do with Rcpp. Your class A is simply "too virtual". If I combine your files A.h and A.cpp with a simple main.cpp of this form
#include <cstdio>
int main(int argc, char *argv[]) {
std::printf("Hello, world.");
}
and try to compile it I also get an error:
edd#rob:/tmp$ g++ -o A A.cpp main.cpp
/usr/bin/ld: /tmp/ccbuZv0r.o: in function `A::A()':
A.cpp:(.text._ZN1AC2Ev[_ZN1AC5Ev]+0xf): undefined reference to `vtable for A'
/usr/bin/ld: /tmp/ccbuZv0r.o: in function `B::~B()':
A.cpp:(.text._ZN1BD2Ev[_ZN1BD5Ev]+0x26): undefined reference to `A::~A()'
/usr/bin/ld: /tmp/ccbuZv0r.o:(.data.rel.ro._ZTI1B[_ZTI1B]+0x10): undefined reference to `typeinfo for A'
collect2: error: ld returned 1 exit status
edd#rob:/tmp$
Which is pretty much what you got from R as well
edd#rob:/tmp$ c++filt _ZTI1A
typeinfo for A
edd#rob:/tmp$
So your package was simply insufficient -- nothing to do with Rcpp.