Loading derived polymorphic class using dlopen

In a C++ code I'm trying to have a main module that defines a polymorphic base class, which dynamically loads derived classes for it at runtime. The main module has something like:

class Base {
public:
    virtual ~Base();
    virtual int f() = 0;
};

int main() {
    auto make_a_ptr = /* load function pointer make_a from module using dsym */;
    Base* a = make_a_ptr();
    std::cout << a->f() << std::endl;
    delete a;
}

The dynamically loaded external module has:

class A : public Base {
public:
    int f() {
        return 123;
    }
};

extern "C" Base* make_a() {
    return new A;
}

Will a system like this work on Linux, without additional steps regarding the dynamic linking? Because here only make_a is explicitly loaded using dlsym(), but the main module will also call A::f() and A::~A(), and access the v-table of A. Will this still work even though those symbols were not explicitly loaded?

And is a similar system possible on Windows platform?

Solution

In a C++ code I'm trying to have a main module that defines a polymorphic base class, which dynamically loads derived classes for it at runtime.

So far, so good. Beware all the usual caveats - among them are:

Use the same compiler and library versions when compiling plugins. At the very least make sure the ABIs are compatible.
Link to a shared c++ runtime when doing this on windows.
windows will require ddlexport/dllimport attributes on declarations.
compile linux shared libraries with -fPIC
be sure to lazy-load symbol names so as to avoid conflicts (e.g. if 2 shared libs have an exported function called make_a.

Will a system like this work on Linux, without additional steps regarding the dynamic linking?

Yes

And is a similar system possible on Windows platform?

Yes. Again, see caveats and do some research.

Some good answers here: Is there an elegant way to avoid dlsym when using dlopen in C?