如何在C ++中跟踪NaN [英] How to trace a NaN in C++

问题描述

我将使用C ++做一些数学计算。输入浮点数是有效数字，但在计算后，结果值为NaN。我想跟踪NaN值出现的点（可能使用GDB），而不是在代码中插入大量的 isNan（）。但是我发现，即使这样的代码，当NaN值出现时也不会触发异常。

  double dirty = 0.0; 
 double nanvalue = 0.0 / dirty; 
  

任何人都可以建议一种跟踪NaN或将NaN变成异常的方法？

在Visual Studio中，您可以使用_controlfp函数设置浮点计算的行为（参见 msdn.microsoft.com/en-us/library/e9b52ceh(VS.80).aspx\">http://msdn.microsoft.com/en-us/library/e9b52ceh(VS.80).aspx ）。也许你的平台有一个类似的变体。

I am going to do some math calculations using C++ . The input floating point number is a valid number, but after the calculations, the resulting value is NaN. I would like to trace the point where NaN value appears (possibly using GDB), instead of inserting a lot of isNan() into the code. But I found that even code like this will not trigger an exception when a NaN value appears.

double dirty = 0.0;
double nanvalue = 0.0/dirty;

Could anyone suggest a method for tracing the NaN or turning a NaN into an exception?

解决方案

In Visual Studio you can use the _controlfp function to set the behavior of floating-point calculations (see http://msdn.microsoft.com/en-us/library/e9b52ceh(VS.80).aspx). Maybe there is a similar variant for your platform.

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