表达式太复杂???

liub1979

 其实是很简单的一个函数调用

我用vc编了一个vb能够调用dll

程序如下

double __stdcall Distance2D(double x1 , double y1 , double x2 , double y2 )
{
    double distance;
    double a, b;
    a = pow(x1 - x2,2);
    b = pow(y1 - y2,2);
    distance = fabs (sqrt (a + b));
 return distance;
}

我在vb下调用如下

Private Declare Function Distance2D Lib "ACMTDLL" (ByVal x1 As Double, ByVal y1 As Double, _
                                                   ByVal x2 As Double, ByVal y2 As Double) As Double
Sub Main()
    Dim d As Double
    d = Distance2D(0#, 0#, 1#, 1#)
End Sub
可以得到正确结果

可是在vba里运行时 便出现以下错误提示

       运行时错误16 表达式太复杂

不知是什么原因啊表达式很复杂吗? 有那位大虾赐教一下!