🚀 go-pugleaf

In article <C1GHJy.GJp@x.co.uk> clive@x.co.uk (Clive Feather) writes:
>In article <1993Jan26.013634.20451@nntpd.lkg.dec.com> diamond@jit.dec.com (Norman Diamond) writes:
>>In article <1993Jan25.213543.25499@pony.Ingres.COM> mikes@Ingres.COM (Mike Schilling) writes:
>>>(a) Each scalar type has an unambiguous alignment requirement.

>>For all existing C compilers?  Probably.  For all hypothetical standard
>>conforming compilers?  Uncertain.  Actually it is imaginable, for a
>>hypothetical but really meaningful compiler, if space is virtually free
>>but speed is extremely expensive, one might want to align a 4-byte integer
>>in the second half of an 8-byte cache line in order to save time by only
>>filling half of a cache line.  I don't know if you'd call this unambiguous.

>ISO 3.1 defines alignment as the requirement for objects of a given type
>to have addresses that are multiples of some number.

You're right!  So does ANSI Classic 1.6.  There goes that possible
optimization.

>There are no
>requirements for alignment that I can find, except that 6.5.2.1 requires
>the alignment of structure members to be defined by the implementation.

That is indeed the (mostly) relevant section, since the original question
was asking about structure members.  The implementation can choose an
arbitrarily obscure alignment technique, as long as it documents it.
However, I don't know if that makes it "unambiguous".
--
Norman Diamond                diamond@jit.dec.com
If this were the company's opinion, I wouldn't be allowed to post it.
Pardon me?  Or do I have to commit a crime first?