Re: [Qemu-trivial] [Qemu-devel] [PATCH v5 01/46] include: Add IEC binary prefixes in "qemu/units.h"

[Eric Blake <eblake@redhat.com>]

On 06/27/2018 06:27 AM, Igor Mammedov wrote:
> On Mon, 25 Jun 2018 09:41:53 -0300
> Philippe Mathieu-Daudé <f4bug@amsat.org> wrote:
> 
>> Loosely based on 076b35b5a56.
>>
>> Suggested-by: Stefan Weil <sw@weilnetz.de>
>> Signed-off-by: Philippe Mathieu-Daudé <f4bug@amsat.org>
>> ---

>> +#ifndef QEMU_UNITS_H
>> +#define QEMU_UNITS_H
>> +
>> +#define KiB     (INT64_C(1) << 10)
>> +#define MiB     (INT64_C(1) << 20)
>> +#define GiB     (INT64_C(1) << 30)
>> +#define TiB     (INT64_C(1) << 40)
>> +#define PiB     (INT64_C(1) << 50)
>> +#define EiB     (INT64_C(1) << 60)
> Shouldn't above use UINT64_C()

Since the decision of signed vs. unsigned was intentional based on 
review on earlier versions, it may be worth a comment in this file that 
these constants are intentionally signed (in usage patterns, these tend 
to be multiplied by another value; and while it is easy to go to 
unsigned by doing '1U * KiB', you can't go in the opposite direction if 
you want a signed number for '1 * KiB' unless KiB is signed).

-- 
Eric Blake, Principal Software Engineer
Red Hat, Inc.           +1-919-301-3266
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