Can I use memcpy in C++ to copy classes that have no pointers or virtual functions

Question

Say I have a class, something like the following;

class MyClass
{
public:
  MyClass();
  int a,b,c;
  double x,y,z;
};

#define  PageSize 1000000

MyClass Ar         


        

Answer 1

Your class has a constructor, and so is not POD in the sense that a C struct is. It is therefore not safe to copy it with memcpy(). If you want POD data, remove the constructor. If you want non-POD data, where controlled construction is essential, don't use memcpy() - you can't have both.