From: "Richard W.M. Jones" <rjones@redhat.com>
To: Laszlo Ersek <lersek@redhat.com>
Cc: Kevin Wolf <kwolf@redhat.com>,
Peter Maydell <peter.maydell@linaro.org>,
Jeff Cody <jcody@redhat.com>,
QEMU Developers <qemu-devel@nongnu.org>,
Alexander Graf <agraf@suse.de>,
Stefan Hajnoczi <stefanha@redhat.com>
Subject: Re: [Qemu-devel] [PATCH] block: Explicitly specify 'unsigned long long' for VHDX 64-bit constants
Date: Fri, 14 Mar 2014 16:51:09 +0000 [thread overview]
Message-ID: <20140314165109.GV1346@redhat.com> (raw)
In-Reply-To: <53232D9E.2010002@redhat.com>
On Fri, Mar 14, 2014 at 05:26:06PM +0100, Laszlo Ersek wrote:
> (b) UINT64_C() is for "uint_least64_t" (7.18.4.1 Macros for
> minimum-width integer constants). "uint_least64_t" is a required type
> (7.18.1.2 Minimum-width integer types).
>
> In practice I'd say it doesn't matter which one we use:
> - ULL suffix is gnu89,
> - UINT64_C() macro is gnu89,
> - "unsigned long long" could be wider in general than 64 bits,
> - "uint_least64_t" too could be wider in general than 64 bits,
> - for us both results in uint64_t exactly.
>
> So the above is a tie, but the ULL suffix is just nicer. (IMHO :))
Interesting discussion here:
https://stackoverflow.com/questions/16360828/what-is-the-purpose-of-macros-for-minimum-width-integer-constants
suggesting that these macros aren't well-specified. Ho hum.
Rich.
--
Richard Jones, Virtualization Group, Red Hat http://people.redhat.com/~rjones
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next prev parent reply other threads:[~2014-03-14 16:51 UTC|newest]
Thread overview: 19+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-03-14 10:50 [Qemu-devel] [PATCH] block: Explicitly specify 'unsigned long long' for VHDX 64-bit constants Jeff Cody
2014-03-14 15:25 ` Stefan Hajnoczi
2014-03-14 15:36 ` Richard W.M. Jones
2014-03-14 15:38 ` Peter Maydell
2014-03-14 15:57 ` Richard W.M. Jones
2014-03-14 16:26 ` Laszlo Ersek
2014-03-14 16:51 ` Richard W.M. Jones [this message]
2014-03-14 17:27 ` Laszlo Ersek
2014-03-14 17:49 ` Richard W.M. Jones
2014-03-14 18:16 ` Laszlo Ersek
2014-03-14 16:17 ` Laszlo Ersek
2014-03-14 16:26 ` Peter Maydell
2014-03-14 16:35 ` Laszlo Ersek
2014-03-14 16:36 ` Laszlo Ersek
2014-03-14 17:08 ` Peter Maydell
2014-03-14 17:42 ` Laszlo Ersek
2014-03-14 18:22 ` Peter Maydell
2014-03-14 18:49 ` Laszlo Ersek
2014-03-14 18:57 ` Laszlo Ersek
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