c# - C# (.Net) 是否区分信号 NaN 和静默 NaN？

Question

C# 是否区分信号 NaN 和静默 NaN？

如果是这样，我如何调用两者并检查属性？

Answer 1

没有。我在规范或代码中找不到任何对 Quiet 或 Signaling NaN 的引用。

规范没有提到不同的 NaN 类型。来自 4.1.6 Floating point types :

The Not-a-Number value, often abbreviated NaN. NaN's are produced by invalid floating-point operations, such as dividing zero by zero.

源代码中的几个示例:

• Double.NaN :

  public const double NaN = (double)0.0 / (double)0.0;
  

• Double.IsNaN :

  return (*(UInt64*)(&d) & 0x7FFFFFFFFFFFFFFFL) > 0x7FF0000000000000L;
  

• Math.IEEERemainder(double x, double y) :

  public static double IEEERemainder(double x, double y) {
      if (Double.IsNaN(x)) {
          return x; // IEEE 754-2008: NaN payload must be preserved
      }
      if (Double.IsNaN(y)) {
          return y; // IEEE 754-2008: NaN payload must be preserved
      }
  
      double regularMod = x % y;
      if (Double.IsNaN(regularMod)) {
          return Double.NaN;
      }
      // ...
  }