VarRound implementation

Dmitry Timoshkov dmitry at
Fri Feb 20 08:53:08 CST 2004

"Fabian Cenedese" <Cenedese at> wrote:

> For this I tested more cases on Windows and got strange results (in my view).
> VT_R4: 7.850 -> VarRound(1) -> 7.800
> VT_R4: 7.851 -> VarRound(1) -> 7.900
> Is this the binary representation (in)accuracy?
> How can I test if the rounding worked ok when the numbers may differ in
> the last (invisible) bits?
> And how should I round a currency? It's valid on Windows but I couldn't
> interpret the results. Is this some kind of fixed comma type?

dlls/oleaut32/tests/vartype.c around line 4514 has the following comment:

    /* MSDN states that rounding of R4/R8 is dependent on the underlying
     * bit pattern of the number and so is architecture dependent. In this
     * case Wine returns .2 (which is more correct) and Native returns .3

So, I'd suggest just surround your test by todo_wine and add a comment
explaining the situation.


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