Windows NT Muldiv() Function Returns Incorrect Value

ID: Q159093

The information in this article applies to:

Microsoft Windows NT Workstation version 4.0
Microsoft Windows NT Server version 4.0

SYMPTOMS

Muldiv(0,0,-1) returns -1 when it should be 0. The MulDiv function multiplies two 32-bit values and then divides the 64-bit result by a third 32-bit value. The return value is rounded up or down to the nearest integer.


int MulDiv(
    int nNumber,        // 32-bit signed multiplicand
    int nNumerator,     // 32-bit signed multiplier
    int nDenominator    // 32-bit signed divisor

Parameters

nNumber: Specifies the multiplicand.

nNumerator: Specifies the multiplie

nDenominator: Specifies the number by which the result of the multiplication (nNumber * nNumerator) is to be divided.

Return Values

If the function succeeds, the return value is the result of the multiplication and division. If either an overflow occurred or nDenominator was 0, the return value is -1.

CAUSE

The multiplier is positive, the multiplicand is positive, the divisor is negative. The result is negative when actually, the result was positive (0).

STATUS

Microsoft has confirmed this to be a problem in Microsoft Windows NT version 4.0. This problem was corrected in the latest Microsoft Windows NT 4.0 U.S. Service Pack. For information on obtaining the service pack, query on the following word in the Microsoft Knowledge Base (without the spaces):

S E R V P A C K

Additional query words: prodnt

Keywords : kbenv kbbug4.00 kbfix4.00.sp2 NTSrvWkst
Version : 4.0
Platform : winnt
Issue type :