Re: [PATCH] tools/libxl: Fix the errno

[Ian Campbell <ian.campbell@citrix.com>]

On Fri, 2015-03-20 at 11:03 +0000, Ian Campbell wrote:
> Do the new callers actually need the number of bytes read/written or was
> this just something which seemed like a good idea since it was in hand?
> 
> If it isn't needed

In fact, irrespective of the needs of the future callers lets go back to
the old semantics of errnoval for now, since it should be a quick and
easy patch, I think.

Then if it is actually needed we can sort out the propagation of the
number of bytes read in a new patch as part of that series.

>  then lets go back to the old semantics and pass 0 on
> EOF or bytes_to_read have been read (essentially "0 bytes left to
> read"), I expect the recipient of the callback should know (or could
> remember) the initial value of bytes_to_read? 
> 
> Otherwise I think the only sensible approach would be to add a new
> parameter to the callback for the number of bytes and but errnoval back
> to the old semantics.
> 
> Or perhaps requiring a separater callback vs. pollhup_callback could
> solve this too, they would have different prototypes.
> 
> Please can one of you look into this ASAP, otherwise I think we should
> revert until it can get fixed.
> 
> Ian.