Difference between "char *arr" and "char arr[]"

[Sean Fagan]

In article <ENAG.90Sep25005953 at hild.ifi.uio.no> enag at ifi.uio.no (Erik Naggum) writes:
>Rather, "char arr[14]" declares an array, but "extern char arr[]" only
>declares that "arr" is some constant pointer the value of which is to
>be resolved by the linker.  

*NO NO NO NO*!

'extern char arr[]' does *not* declare, in any way, shape, or form, a
pointer.

What it *does* declare is the label of a block of memory (size currently
unknown), which will be (hopefully) resolved at link time.

The difference between

	extern char arr[];

and

	extern char *ptr;

is that the first one is not indirected to get the address; the other one
is.  That is, ptr is actually a double-indirect variable:  one indirection
to get its value, and another one to dereference it.  arr, on the other
hand, is just indirected once, to get it's value (which is arr[0]).

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