How can I tell if an object is statically or dynamically allocated on the constructor? [duplicate]

Answer 1

I don't think you can tell in the constructor.

I don't know if this helps, but you can prevent the object from being statically created by making the destructor private. You would also need to have a public "Delete" method that does a delete this for code that dynamically allocates objects of this class -- they would have to do an obj->Delete() rather than delete obj.

Answer 2

Any constructor can be used for static or dynamic allocation. There is no way for you to force the user of the object to use a particular constructor, whichever way he allocates the object.

Answer 3

You should be able to achieve what you want while leaving a single user-accessible default constructor (which will be used for static and auto objects -- you appear to ignore the existence of auto objects, e.g. local variables, so I imagine you want to treat these cases the same).

Make operator new and a separate constructor both private, and make a public static method (it's a case of the "factory method" design pattern) which only does a return new TheClass(123); (assuming the separate constructor takes for example an integer, but of course you can pick any type of argument you want, as the argument isn't used anyway).

You know you said the object should have a single constructor, but from the user's point of view that's exactly of the class is behaving, and there's no "explicit selection of constructor" on the user's part (he just can't call new explicitly but must go through your supplied factory method, that's all).