Error deleting std::vector in a DLL using the PIMPL idiom

Question

I have the following code:

In DLL1:

in .h file:

class MyClass
{
public:
    MyClass();
private:
    std::string m_name;
};

class __declspec(dlle         


        

Answer 1

Without further code available for analysis, an important bug I see in your posted code is that your Foo class is a resource manager violating the so called Rule of Three.

Basically, you dynamically allocate an Impl instance in the Foo constructor using new, you have a virtual destructor for Foo releasing the managed resource (pimpl) with delete, but your Foo class is vulnerable to copies.
In fact, the compiler generated copy constructor and copy assignment operators perform member-wise copies, which are basically shallow-copies of the pimpl pointer data member: this is a source of "leaktrocities".

You may want to declare private copy constructor and copy assignment for Foo, to disable compiler-generated member-wise copy operations:

// Inside your Foo class definition (in the .h file):
...

// Ban copy
private:
    Foo(const Foo&); // = delete
    Foo& operator=(const Foo&); // = delete

Note: The C++11's =delete syntax to disable copies is not available in MSVC 2010, so I embedded it in comments.

---

Not directly related to your problem, but maybe worth noting:

1. In your Foo::Impl structure, since the m_vec data member is already public, I see no immediate reason to provide an accessor member function like GetVector().

2. Starting with C++11, consider using nullptr instead of NULL in your code.