[MOAB-dev] [Itaps-users] [PATCH 1/2] iMesh_MOAB: do not allocate new memory for count=0 items

[James Porter]

On Fri, 2011-06-10 at 20:30 +0200, Jed Brown wrote:
> Suppose you pass in an undefined/stale array pointer and set the
> allocated size to 0. If the implementation finds that the expected
> length is actually zero, should it still set your pointer? I think it
> should not because the caller would have to put an if statement around
> every call that might handle zero-length arrays.

I honestly can't think of any case where an undefined array pointer is
"safer" than a null array pointer. If you're iterating over a zero-sized
array, you'll just never enter the body of the loop; no extra handling
required. If you're doing something that would barf on a null pointer,
an undefined pointer is going to be even worse, since you'll almost
certainly be accessing an invalid memory location. A stale pointer value
will also be bad in nearly every similar situation, since you'll
probably end up writing to the wrong place in memory.

Could you provide an example of a case where an undefined pointer would
be ok, but a null pointer would cause problems?

- Jim