Re: [Qemu-devel] [RFC PATCH v4 07/30] Add SIZE type to qdev properties

[li guang]

在 2013-03-20三的 08:24 -0600，Eric Blake写道：
> 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.
> 

Yes, you're right,
amazing c type cast!