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Date: Wed, 31 Aug 2011 10:38:48 -0700
From: "H. Peter Anvin" <hpa@zytor.com>
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To: Linus Torvalds <torvalds@linux-foundation.org>
CC: Arnd Bergmann <arnd@arndb.de>, Christoph Hellwig <hch@infradead.org>,
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        Ingo Molnar <mingo@elte.hu>, Thomas Gleixner <tglx@linutronix.de>,
        Richard Kuo <rkuo@codeaurora.org>, Mark Salter <msalter@redhat.com>,
        Jonas Bonn <jonas@southpole.se>, Tobias Klauser <tklauser@distanz.ch>
Subject: Re: RFD: x32 ABI system call numbers
References: <4E582577.2060805@zytor.com> <201108301409.27527.arnd@arndb.de> <4E5D1153.5030908@zytor.com> <201108311814.54906.arnd@arndb.de> <CA+55aFxfmwfB7jbbrXxa=K7VBYPfAvmu3XOkGrLbB1UFjX1+Ew@mail.gmail.com> <4E5E6AC0.60000@zytor.com> <CA+55aFzEnGb3G2WeVNoS5e2D4poY5O6gJucnVnFRF51NUYkW8A@mail.gmail.com>
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On 08/31/2011 10:19 AM, Linus Torvalds wrote:
> 
> I think tv_nsec was just overlooked, and people thought "it has no
> legacy users that were 'int', so we'll just leave it at 'long', which
> is guaranteed to be enough for nanoseconds that only needs a range of
> 32 bits".
> 
> In contrast, tv_usec probably *does* have legacy users that are "int".
> 
> So POSIX almost certainly only looked backwards, and never thought
> about users who would need to make it "long long" for compatibility
> reasons.
> 
> The fact that *every*other*related*field* in POSIX/SuS has a typedef
> exactly for these kinds of reasons just shows how stupid that "long
> tv_nsec" thing is.
> 
> I suspect that on Linux we can just say "tv_nsec" is suseconds_t too.
> Then we can make time_t and suseconds_t just match, and be "__s64" on
> all new platforms.
> 

Let me see if I can raise this with the POSIX committee.

	-hpa


-- 
H. Peter Anvin, Intel Open Source Technology Center
I work for Intel.  I don't speak on their behalf.