segmentation violation due to unnoticed invalid code ?

[Nathan Sidwell]

Alexandre Oliva wrote:
> 
> On Apr 13, 1999, Luc.Maisonobe@cnes.fr (Luc Maisonobe) wrote:
> 
> >   A *a     = new A [1];
> >   delete [] ((void *) a);
> 
> When you new an array, you must delete[] it using a pointer of the
> actual type of the array elements.  Since A is not void, the behavior
> is undefined.

> > Of course this is weird code (it has been corrected since then), but I
> > would suggest egcs should complain about freeing an anonymous pointer.
> 
> Yep, it would probably be a nice feature, since `delete[] (void*)foo'
> can *never* be well-defined behavior, as `new void[n]' is ill-formed.

I believe both `delete (void *)e' and `delete[] (void *)e' to be undefined. The
former is because the static type (void) must be different to the dynamic type
of the object (fails first part of 5.3.5/3) The latter is also undefined
because of the second part of 5.3.5/3 as footnote 73 notes.

So, we could warn on both instances. I guess there might be some code using
`delete e' to deallocate random blobs of memory, but shouldn't they use
`operator delete(e)' instead?

nathan

-- 
Dr Nathan Sidwell :: Computer Science Department :: Bristol University
      You can up the bandwidth, but you can't up the speed of light      
nathan@acm.org  http://www.cs.bris.ac.uk/~nathan/  nathan@cs.bris.ac.uk