extern variable assignment

[George2]

Hello everyone,


Statement like this,

extern int i = 3;

1. Is it correct?

2. Is it definition or declaration? Any special function or benefits we could get compared with

extern int i; or
int i = 3


thanks in advance,
George

 

[vijayan]

> extern int i = 3;
> Is it correct?
yes.
> Is it definition or declaration?
it is both.

extern int i; // declaration
int i=3 ; // definition

> Any special function or benefits we could get
not really. by default i would have external linkage; so

extern int i = 3 ;

and

int i = 3 ;

are equivalent.

extern const int c = 3 ;

here, without the extern, c would have intenal linkage (constant).

 

[George2]

Thanks vijayan,

c would have intenal linkage (constant).

Sorry I do not quite understand your points above. Could you show me the code of external/internal linkage please?

BTW: I have this confusion is because, for global variables and functions, if we do not add extern, it is by default added, and static (on the other side) is not as default. So I am confused what do you mean if extern is not added, the linkage will changed from external to internal? Internal means static?


regards,
George