Sizeof static member object?

Why can't I use sizeof on foo::i in a member function but I can use it in main()?

Code:

---

#include <iostream>

class foo {
public:
        static int i[];

        void bar()
        {
                int s = sizeof(i); //gives error C2070: 'int []': illegal sizeof operand
        }
};

int foo::i[] = {1,2,3};

int main()
{
        int s = sizeof(foo::i);
}

---

You cannot take sizeof on an incomplete type. Until you initialize foo::i, it's length is unknown, hence its type is unknown. So the lookup in main works, since at that time foo::i is an int[3]; but the lookup in bar fails, since at that time foo::i is an int[]. ETA: You should be able to make it work if either (a) you move the definition of bar below the initialization of i, or (b) give i a size in its declaration.

Probably because at that point in the file, the sizeof i is indeed unknown.

You may try moving the implementation of bar below the definition of i.