Re: [PATCH 08/11] xfsprogs: replace obsolete memalign with posix_memalign

[Jan Tulak <jtulak@xxxxxxxxxx>]

On Mon, Aug 17, 2015 at 9:36 PM, Christoph Hellwig <hch@xxxxxxxxxxxxx> wrote:

On Mon, Aug 17, 2015 at 06:23:23PM +0200, Jan Tulak wrote:
> Memalign from <malloc.h> was marked obsolete in favor of a posix
> variant from <stdlib.h>. So replace all calls and remove <malloc.h>
> includes. This also enhances support on other posix platforms,
> which doesn't have <malloc.h>.
>
> Because posix_memalign returns any error as a return code, not in
> errno, change relevant checks in code (and add a missing one).

I have to say I hate the posix_memalign calling convention. Any chance
you could just provide a memalign impementation using posix_memalign for
MacOS?

I thought about it. However, with memalign from malloc marked obsolete

(and with posix_memalign having guaranteed alignment restrictions [1]), I saw it better

to use the posix variant everywhere.

I could make a wrapper simulating the old memalign behaviour, but I don't

think it would make sense.

I searched for this, but didn't find any reasonable answer:

How long can be things in standard libraries marked obsolete before removing?

Cheers,

Jan

[1] man memalign:

   ÂOn many systems there are alignment restrictions, for example, on Âbufâ

   Âfers Âused Âfor Âdirect Âblock Âdevice ÂI/O. POSIX specifies the pathâ

   Âconf(path,_PC_REC_XFER_ALIGN) call that tells what alignment is needed.

   ÂNow one can use posix_memalign() to satisfy this requirement.

   Âposix_memalign() Âverifies Âthat Âalignment Âmatches Âthe Ârequirements

   Âdetailed above. Âmemalign() may not check that the Âalignment Âargument

   Âis correct.

--

Jan Tulak

jtulak@xxxxxxxxxx