🚀 go-pugleaf

In article <4jq1e4$a2g@solutions.solon.com>
           David_McReynolds@vos.stratus.com "David McReynolds" writes:

>Perhaps I'm confused but when I read the question this is what I came
>up with.  It compiles and worked as expected in a test case.
>
>As far as the two pointers to be swapped are concerned, they are of
>the same type correct?
>
>I do not see the problem with:
>
>void swap_ptr(void **p1, void **p2) {
>  void *tmp = *p1;
>
>  *p1 = *p2;
>  *p2 = tmp;
>
>  return;
>}

This swaps 2 void * pointers, it isn't guaranteed to swap any other type
of pointer (except possibly char *). There is no guarantee that any other
pointer has the same size or representation as void * (except char *).

>Granted I did not do an extensive test but I did try ints, chars and floats
>with no surprises. As in:

You're assuming that all non-function pointers at least have the same size if
not the same representation. That may well hold on your platform but isn't
true in general. As far as the C language is concerned your code invokes
undefined behaviour and is not portable.

>Could someone enlighten me as to why this thread is so long?

Well, a couple of the articles suggest systems where your assumption
doesn't hold.

-- 
-----------------------------------------
Lawrence Kirby | fred@genesis.demon.co.uk
Wilts, England | 70734.126@compuserve.com
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