How to re-throw an abstract class error from a catch block

I need to perform some action inside a catch block then throw the same exception I got:

#include <string>
#include <iostream>
class AbstractError {
public:
    virtual std::string toString() const = 0;
};

class SomeConcreteError : public AbstractError { public:
    std::string toString() const { return "division bt 0"; }
};

class SomeOtherError : public AbstractError { public:
    std::string toString() const { return "null pointer deref"; }
};

void foo(int i)
{
    if (i > 2) { throw SomeConcreteError(); }
    else       { throw SomeOtherError();    }
}

int main(int argc, char **argv)
{
    try { foo(argc); }
    catch (const AbstractError &e)
    {
        std::cout << e.toString() << "\n"; // do some action then re-throw
        // throw e; doesn't work ...
    }
    return 0;
}

Here is the error I get:

main.cpp:28:15: error: expression of abstract class type ‘AbstractError’ cannot be used in throw-expression
   28 |         throw e;
      |               ^

>Solution :

This would throw a copy of e:

throw e;

but it’s abstract so that can’t be done. You need to rethrow the same exception:

throw;