Thread: Question about "Extern const"

I define:

Code:

extern const int i2 = 110;

in C++, compiler reports an error as:

error C2205: 'i2' : cannot initialize extern variables with block

What does it mean?

Can I do this:

Code:

// xx.h
extern const int I2;

// xx1.cpp
#include "xx.h"
const int I2 = 110;


// xx2.cpp
#include "xx.h"
const int I2 = 220;

What will happen? Are there conflictions?
If not, seems that "extern const" doesn't make any sense, because you can always define:

Code:

// xx1.cpp
const int I3 = 110;


// xx2.cpp
const int I4 = 220;

What's the point of using "extern const"?