[PATCH] string: Add tests for zero length string inputs

[Richard Earnshaw]

On 23/09/14 13:41, Florian Weimer wrote:
> On 09/22/2014 06:09 PM, Richard Earnshaw wrote:
>>> These tests are not testing null pointers, they are testing that when
>>> given a zero length the functions actually read/write zero bytes.
>>> Whether the specification demands that behaviour is arguable but I
>>> believe that it is the most sane behaviour.
> 
>> Valid pointers is more than just non-NULL.  In particular, it implies
>> that is safe to dereference the addressed byte in a source operand even
>> when the length parameter is zero.
> 
> Valid pointers can also point one element past the end of an array of 
> objects.  

I don't think such a pointer forms a valid argument for a library
function though.  See my previous reply to Paul.

> Such pointers can occur naturally during the final iteration 
> of buffer-processing loops.  I don't think it is reasonable to expect 
> that programmers write special code (or at least early loop exits) to 
> deal with this corner case.  This has to work, and if the C standard 
> does not guarantee it does, it needs fixing.
> 
>> Thus testing that no bytes are read would be incorrect.
> 
> I disagree, per the above.
> 

R.