🚀 go-pugleaf

In article <jamesc.724907666@bart> jamesc@swapsdev.state.state.COM.AU (James Cribb) writes:
>Suppose a single struct Something needed 7 bytes of memory.  For word
>alignment, these might need to start on, say, 4-byte boundaries.
>Do the standards guarantee that sizeof(struct Something) will always be
>8 rather than 7?

Yes.  ANSI's original C standard section 3.5.2.1, page 62 lines 2 to 3:
"Each non-bit-field member of a structure or union object is aligned in an
implementation-defined manner appropriate to its type."  Lines 13 to 14:
"There may also be unnamed padding at the end of a structure or union, as
necessary to achieve the appropriate alignment were the structure or union
to be an element of an array."

If it is appropriate for a member type to be aligned on a 4-byte boundary,
then the implementation-defined manner will result in such alignment,
including if necessary a padding byte at the end of the structure.
--
Norman Diamond       diamond@jit081.enet.dec.com
If this were the company's opinion, I wouldn't be allowed to post it.
"It's been a lovely recession."