From:	Don DOT Sharp AT dddandr DOT octacon DOT co DOT uk (Don Sharp)
Subject:	Re: pointers &arrays[]
25 Nov 1997 07:27:54 -0800 :
Message-ID:	<3479537F.4F304E35.cygnus.gnu-win32@dddandr.octacon.co.uk>
References:	<199711210929 DOT EAA01841 AT p2 DOT acadia DOT net>
Mime-Version:	1.0
To:	Scott Warner <swarnerx3 AT acadia DOT net>
Cc:	gnu-win32 <gnu-win32 AT cygnus DOT com>

Scott Warner wrote:
> 
> In a recent chat room discussion, pointer notation of arrays in C was
> brought up.  The question is, are array names pointers?  Is array
> subscripting another form of pointer notation, or visa-versa?  I
> realize
> the pointer notation works for everything except sizeof() (and maybe
> others).  So that
> 
> array == &array[0]
> array == &array
> *array == array[0]
> *(array+n) == array[n]
> 
> are all true given array[n].  In this case, sizeof(array) returns the
> size
> of the entire array, not array[0].  Are there other examples where
> this
> pointer notation fails?
> Lastly, is this pointer notation implementation dependent or is it
> part of
> the de facto standard?
> 

Pointers and array names are only EXACTLY equivalent (in C) when used
as arguments to functions. Most compilers preserve this assumption
outside that case but don't have to.

I've been caught out at link time by referencing

extern char *freddy_the_freeloader;

when it had in fact been declared as

char freddy_the_freeloader[] = "nice jazz tune";

the linker quite rightly ruled that they are not the same thing!

Cheers

Don Sharp

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