about external linkage question

[Kurt]

The C++ standard (in 3.5:6, p42Example) said:

static int i = 0; //
1
void g()
{
int i; //2: i has no linkage

{
extern int i; //3: external linkage
}
}

There are three objects named i. The object with internal
linkage
(line //1); the object with automatic storage duration and no
linkage (line //2); the object with static storage duration
and
external linkage (line //3).

question is:

I wonder the object i in line //3 refer to i in line //1. But
the
above said they are different thing.
help.

 

[Jonathan Lane]

The C++ standard (in 3.5:6, p42Example) said:

static int i = 0; //
1
void g()
{
int i; //2: i has no linkage

{
extern int i; //3: external linkage
}
}

There are three objects named i. The object with internal
linkage
(line //1); the object with automatic storage duration and no
linkage (line //2); the object with static storage duration
and
external linkage (line //3).

question is:

I wonder the object i in line //3 refer to i in line //1. But
the
above said they are different thing.
help.

Well it should be easy to determine if they're the same. Modify one
and test the value of the other. In this case they aren't. The extern
keyword effectively means, I've declared this in some other file, go
and find it there.