adding virtual function to the end of the class declaration avoids binary incompatibility?
- by bob
Could someone explain to me why adding a virtual function to the end of a class declaration avoids binary incompatibility?
If I have:
class A
{
public:
virtual ~A();
virtual void someFuncA() = 0;
virtual void someFuncB() = 0;
virtual void other1() = 0;
private:
int someVal;
};
And later modify this function to:
class A
{
public:
virtual ~A();
virtual void someFuncA();
virtual void someFuncB();
virtual void someFuncC();
virtual void other1() = 0;
private:
int someVal;
};
I get a coredump from another .so compiled against the previous declaration. But if I put someFuncC() at the end of the class declaration (after "int someVal"), I don't see coredump anymore. Could someone tell me why this is? And does this trick always work?
PS. compiler is gcc, does this work with other compilers?
