MulDiv函数到底是用来干什么的啊？

[kevinbobo]

MulDiv函数到底是用来干什么的啊？

[carbon107]

先乘，再除

[kevinbobo]

#define CALCX(x) (MulDiv(x, GetDeviceCaps(m_DC.m_hDC, LOGPIXELSX), 72))
这是干什么用的啊？是什么意思？

[jazy]

算字体大小的吧？一英寸有72个点，这里应该是在是算x个点折合多少象素。

[DentistryDoctor]

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.

MulDiv(a,b,c)
=a*b/c;

[bohut]

MulDiv

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,
int nNumerator,
int nDenominator
);

Parameters
nNumber
[in] Multiplicand.
nNumerator
[in] Multiplier.
nDenominator
[in] 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.