> From: Aravindhan Krishnan <[EMAIL PROTECTED]>
>
> Whats the difference between the following declarations.?
>
> //file 1
> extern int x=8;
>
> // file 2
> extern int x;
>
> (AND)
>
>
> //file 1
> int x=8;
>
> // file 2
> extern int x;
>
> Thanks,
> Aravindhan
>
>
The keyword 'extern' specifies to the compiler that,
the variable 'x' will be found in the symbol table
of another translation unit.
In short, memory is *not* allocated for the variable
with 'extern' storage specifier in that translation unit.
Having said that, please note that extern declaration is
resolved by the linker and not the compiler !
Let's discuss your examples now.
Illustration1:
. file1 : memory for x declared elsewhere
. file2 : memory for x declared elsewhere
perhaps you have a header file that defined x.
since x=8 in file 1, the variable 'x' has been promoted into
the symbol table of translation unit ie. file1.
Illustration2:
. file1: variable 'x' declared
4 bytes of memory allocated for variable x
variable 'x' is in the symbol table of translation unit
ie. file1
. file2: memory for 'x' declared elsewhere
since externs are always global value '8' seen for x.
Hope this helps.
thanks
Saifi.
