Overhead of C++ inheritance with no virtual functions

Question

In C++, what's the overhead (memory/cpu) associated with inheriting a base class that has no virtual functions? Is it as good as a straight up copy+paste of class members?

class a
{
public:
    void get();
protected:
    int _px;
}

class b : public a
{

}

compared with

class a
{
public:
    void get();
protected:
    int _px;
}

class b
{
public:
    void get();
protected:
    int _px;

}

Answer 1

There might a be slight memory overhead (due to padding) when using inheritance compared to copy and past, consider the following class definitions:

struct A
{
  int i;
  char c1;
};

struct B1 : A
{
  char c2;
};


struct B2
{
  int i;
  char c1;
  char c2;
};

sizeof(B1) will probably be 12, whereas sizeof(B2) might just be 8. This is because the base class A gets padded separately to 8 bytes and then B1 gets padded again to 12 bytes.