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Re: [Qemu-devel] [RFC PATCH v4 07/30] Add SIZE type to qdev properties
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From: |
Eric Blake |
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Subject: |
Re: [Qemu-devel] [RFC PATCH v4 07/30] Add SIZE type to qdev properties |
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Date: |
Wed, 20 Mar 2013 08:24:24 -0600 |
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User-agent: |
Mozilla/5.0 (X11; Linux x86_64; rv:17.0) Gecko/20130311 Thunderbird/17.0.4 |
On 03/20/2013 12:06 AM, li guang wrote:
>> + return snprintf(dest, len, "%0.03f%c", (double)*ptr/div, suffixes[i]);
> ^^^^^^ ^^^^^^^^^^^^^^^
>> +}
>> +
>
> IMHO, you may need (double)(*ptr/div), for type cast is right
> associated.
No, the code as written is correct, and your proposal would be wrong.
As written, it is evaluated as:
((double)*ptr) / div
which promotes the division to floating point. Your proposal would do
the division (*ptr/div) as an integral (truncating) division, and only
then cast the result to double.
--
Eric Blake eblake redhat com +1-919-301-3266
Libvirt virtualization library http://libvirt.org
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