Re: [musl] Alignment attribute in headers

[Thorsten Glaser <tg@mirbsd.de>]

Michael Forney dixit:

>Something like
>
>#if __STDC_VERSION__ >= 201112L
>/* use _Alignas */
>#elif defined(__cplusplus) && !defined(__GNUC__)
>/* use alignas */
>#else
>/* use __attribute__((__aligned__(N))) */
>#end

Something I noticed recently while doing m68k alignment work:

The C++ alignas is UB if the specified alignment is smaller
than what the structure would normally have, so adding cautious
alignments can explode in one’s face. ☹ Not only is this really
stupid, but makes it not generally usable, too.

GCC’s attribute, in contrast, (without __packed__) just gets
ignored for those cases.

I haven’t looked at the C11 one.

bye,
//mirabilos
-- 
“It is inappropriate to require that a time represented as
 seconds since the Epoch precisely represent the number of
 seconds between the referenced time and the Epoch.”
	-- IEEE Std 1003.1b-1993 (POSIX) Section B.2.2.2