Re: Standardizes use of empty extents in pure heights and skylines. (issue 7310075)

[David Kastrup]

"Keith OHara" <address@hidden> writes:

> On Wed, 13 Mar 2013 02:44:33 -0700, <address@hidden> wrote:
>
>> If left and right have equal values to start with, C++ is still not
>> required to have left and right receive the same value after
>>
>> left = left*factor + offset;
>> right = right*factor + offset;
>
> The C standard requires the variables to be equal after assignment.
> C99 5.4.2.2: "Except for assignment and cast (which remove all extra
> range and precision), the values of operations with floating operands
> [...] are evaluated to a format whose range and precision may be
> greater than required by the type."

"May be".  It may be greater for left*factor, and not greater for
right*factor.  The reduction of extra precision happens only _after_
adding offset.

-- 
David Kastrup