VBA溢出错误，类型为double，Excel [英] VBA Overflow error with type double, Excel

问题描述

我不知道溢出错误非常好，所以我很失落。

在VBA中编写我正在调用一个VBA函数，它是一个来自dll的C ++函数的包装（我无法访问内部的）。 VBA / C ++函数返回一个double。它是使用数值方法的衍生品估值。

昨天一段时间（但现在可能已经消失），当尝试将函数返回给声明为double的变量时，我得到溢出错误。 但是在错误停止时，我可以看到分配给double的正确值，在本地窗口（8.17 ...）中。而当我将函数返回赋值给一个变体时，我得到相同的值，没有错误，变体类型为Variant / Double。

任何想法在这里可能发生什么？我完全迷失了提前感谢任何想法。 R

编辑：我尝试的另一件事是将CDbl应用于将其分配给变体后的函数返回。这里是一些伪代码，只是为了澄清我的案例：

  Dim db as Double，va as Variant 
 
 db = DerivativeValue（a，b，c ...）
  

这给了溢出但db在本地窗口中具有正确的值，对错误。

  va = DerivativeValue（a，b，c ...）
  pre> 
 
 
没有错误，相同的值。 va是类型Variant / Double 
  va = CDbl（DerivativeValue（a，b，c ...））
  
现在再次溢出在这种情况下，我忘记了在本地人窗口中做了什么，但可能与情况1相同。
解决方案
我的猜测是该函数返回一个看起来像一个double但不是double的值。
 
 
 
变体旨在获取任何类型的值，分配将执行转换。我想知道一个变体的作业是否有效，因为它可以将返回的值转换为双倍。
 
 
 
如果您尝试以下操作，会发生什么：
  va = DerivativeValue（a，b，c ...）
 db = va 
  pre> 
 
 
如果这样工作，它将让您继续开发，而无需等待发现该功能实际返回。
 
 
 
额外点。 double是64位浮点数。如果您有FPU，则可能返回一个80位浮点数。
 
I don't know the overflow error very well, so I'm pretty at a loss here. 

Writing in VBA I'm calling a VBA function, which is a wrapper of a C++ function from a dll (which I have no access to the innards of). The VBA/C++ function returns a double. It is a derivative valuation using numerical methods. 

For a time yesterday (but it may have gone away now) I was getting the overflow error when trying assign the function return to a variable declared as double. But on the error halt, I could see the correct value assigned to the double, in the locals window (8.17...). And when I instead assign the function return to a variant, I get the same value with no error, the variant being type Variant/Double. 

Any idea what could be going on here? I'm completely lost. Thanks in advance for any ideas. R

Edit: One more thing I tried was applying CDbl to the function return when assigning it to the variant. Here's some pseudo code, just to clarify my cases:
Dim db as Double, va as Variant

db = DerivativeValue(a, b, c...) 
This gives the overflow, but db has the correct value in the locals window, on the error. 
va = DerivativeValue(a, b, c...)
No error, same value. va is type Variant/Double
va = CDbl(DerivativeValue(a, b, c...))
Now overflow again. I forgot what va did in the Locals window in this case, but likely it's the same as case 1. 
解决方案
My guess is that the function is returning a value that looks like a double but is not.

Variants are designed to take any type of value and the assignment will perform conversions.  I wonder if the assignment to a variant works because it can convert the returned value to a double.

What happens if you try the following:
va = DerivativeValue(a,b,c...)
db = va
If this works, it will let you continue development without waiting to discover what the function is actually returning.

Extra point.  A double is a 64 bit floating point number.  If you have a FPU, it might be returning an 80 bit floating point number.

                        
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