char s[] = "asdf" and extern char *s in separate files

[Newsgroup - Ann]

Hi gurus,

I have two files compiled together. One file has the following global
definition:

char s[] = "asdf";

Another file has the following declaration:

extern char *s;

Is there anything wrong here? I know that although char* s and char s[] are
not exactly the same, and in most case, they are interchangable. However,
when I use them in separate files, there are problems:

When I assign the value of s to another char * type local variable like

char *p = s;

Instead of the pointer s itself being assigned to the p, the value pointed
by s is assgined to p. That's certainly not my intention. I know roughly to
say, that's because the different view from the two source files, but how is
the detail? Has anybody here ever experienced similar problems? btw, I am
using Visual C++. Could it be a bug of VC++?

News - Ann

[John Harrison]

Re: char s[] = "asdf&quot ; and extern char *s in separate files


"Newsgroup - Ann" <news_ann@yahoo .com> wrote in message
news:3f066d52$1 _1@rcfnews.cs.u mass.edu...[color=blue]
> Hi gurus,
>
> I have two files compiled together. One file has the following global
> definition:
>
> char s[] = "asdf";
>
> Another file has the following declaration:
>
> extern char *s;
>
> Is there anything wrong here? I know that although char* s and char s[][/color]
are[color=blue]
> not exactly the same, and in most case, they are interchangable. However,
> when I use them in separate files, there are problems:[/color]

Not exactly the same means different. The first is an array, the second is a
pointer. Do this

extern char s[]; // s is an array
[color=blue]
>
> When I assign the value of s to another char * type local variable like
>
> char *p = s;
>
> Instead of the pointer s itself[/color]

s is not a pointer.
[color=blue]
> being assigned to the p, the value pointed
> by s is assgined to p.[/color]

That doesn't make sense. The value 'pointed' to by s is a char, how can a
char be assigned to a pointer?
[color=blue]
> That's certainly not my intention. I know roughly to
> say, that's because the different view from the two source files, but how[/color]
is[color=blue]
> the detail?[/color]

There is no detail, your code is wrong so you get incorrect behaviour.
[color=blue]
> Has anybody here ever experienced similar problems? btw, I am
> using Visual C++. Could it be a bug of VC++?[/color]

No, your code is wrong. Fix the code like I explained and if you are still
having problems post the corrected code.
[color=blue]
>
> News - Ann
>[/color]

john