From: Alejandro Colomar <alx.manpages@gmail.com>
To: "Floyd, Paul" <pjfloyd@wanadoo.fr>,
GNU C Library <libc-alpha@sourceware.org>
Cc: linux-man@vger.kernel.org
Subject: Re: Issues in manpage memalign
Date: Fri, 10 Mar 2023 01:35:25 +0100 [thread overview]
Message-ID: <77cfc3d2-cd41-13a7-bdb9-ced179531f33@gmail.com> (raw)
In-Reply-To: <d79b505c-5b19-331c-5b25-d40adc9cc843@wanadoo.fr>
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Hi Paul,
On 3/7/23 23:24, Floyd, Paul wrote:
> Hi
>
> Quick bit of background. I'm a Valgrind maintainer and recently I've
> been working on getting Valgrind to work more like the underlying OS /
> libc implementations of memalign, posix_memalign and aligned_alloc.
>
> There are several issues with the manpage for memalign and aligned alloc.
>
> quote:
>
> The obsolete function memalign() allocates size bytes and
> returns a
> pointer to the allocated memory. The memory address will be a
> multiple
> of alignment, which must be a power of two.
>
> endquote:
>
> The power if two requirement is false for glibc which silently bumps up
> the alignment to the next power of two.
>
> quote:
>
> The function aligned_alloc() is the same as memalign(), except
> for the
> added restriction that size should be a multiple of alignment.
>
> endquote:
>
> This is also false for glibc. In the glibc implementation weak aliases
> are used so memalign and aligned_alloc call the same function.
>
> quote:
>
> ERRORS
> EINVAL The alignment argument was not a power of two, or was not
> a mul-
> tiple of sizeof(void *).
>
> endquote:
>
> Both of the above only apply to posix_memalign and not to either
> memalign or aligned_alloc.
>
> There is a missing EINVAL description. If the alignment is so large that
> the allocation will not be possible to satisfy then the call will fail
> and set errno to EINVAL.
I've CCd glibc, in case someone there can confirm in which direction they
would like the manual page to go.
For now, I'll add a [[deprecated]] attribute in the Synopsis for the
obsolete functions.
Cheers,
Alex
>
>
> Regards
>
> Paul
>
>
--
<http://www.alejandro-colomar.es/>
GPG key fingerprint: A9348594CE31283A826FBDD8D57633D441E25BB5
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next parent reply other threads:[~2023-03-10 0:35 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <d79b505c-5b19-331c-5b25-d40adc9cc843@wanadoo.fr>
2023-03-10 0:35 ` Alejandro Colomar [this message]
2023-03-10 3:02 ` DJ Delorie
2023-03-10 7:21 ` Paul Floyd
2023-03-10 4:05 ` Xi Ruoyao
2023-03-10 7:15 ` Paul Floyd
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