Re: "Wire" definitions and __packed

[<Paul.Koning%dell.com@localhost>]

> On Oct 6, 2016, at 2:01 PM, Joerg Sonnenberger <joerg%bec.de@localhost> wrote:
> 
> On Fri, Oct 07, 2016 at 04:59:30AM +1100, matthew green wrote:
>> John Nemeth writes:
>>> On Oct 6,  3:01pm, matthew green wrote:
>>> }
>>> } >      X86 doesn't have alignment restrictions.  The platform
>>> } > practically lets you get away with murder, and thus is not useful
>>> } > as a test platform.
>>> } 
>>> } FWIW, this hasn't been true since at least 1999 (SSE.)  also,
>>> 
>>>     That only counts if somebody is using SSE, and I highly doubt
>>> that dhcpcd does.
>> 
>> GCC will emit SSE code even if you don't explicitly use them.
> 
> Like for inlined memset or memcpy...

Still, though, the original comment is largely valid: you can't do meaningful testing of changes that affect alignment on an x86 system, because for the most part it doesn't care.  (The same goes for various other CISC machines such as VAX.)  Also, structure padding is different for x86 than for most RISC machines.

The trouble with making a change in fundamental machinery and then doing a "test it to see if it breaks" is that this only exposes issues in the code paths that happened to be touched by the particular test.

	paul