Literals/Floating point: Difference between revisions

There is no built-in support for not-a-number, but here's a way to handle that anyway:

<lang vb>Option Explicit

Public Declare Function RtlCompareMemory Lib "ntdll.dll" _

(ByRef Source1 As Any, ByRef Source2 As Any, ByVal Length As Long) As Long

Public Function IsNAN(ByRef d As Double) As Boolean

Dim d1 As Double

d1 = NaN()

IsNAN = (RtlCompareMemory(d, d1, 8) = 8)

End Function

Public Function NaN() As Double

On Error Resume Next ' ignore the error

NaN = 0 / 0

End Function

Sub Main()

Dim d1 As Double

Dim d2 As Double

d1 = NaN()

d2 = d1

Debug.Assert IsNAN(d2)

Debug.Print CStr(d2)

End Sub</lang>

{{out}}

<pre>-1,#IND</pre>