# Double.IsInfinity(Double) Method

## Definition

Returns a value indicating whether the specified number evaluates to negative or positive infinity.

``````public:
static bool IsInfinity(double d);``````
``````public:
static bool IsInfinity(double d) = System::Numerics::INumberBase<double>::IsInfinity;``````
``public static bool IsInfinity (double d);``
``static member IsInfinity : double -> bool``
``Public Shared Function IsInfinity (d As Double) As Boolean``

#### Parameters

d
Double

A double-precision floating-point number.

#### Returns

Boolean

`true` if `d` evaluates to PositiveInfinity or NegativeInfinity; otherwise, `false`.

## Examples

The following code example illustrates the use of IsInfinity:

``````// This will return S"true".
Console::WriteLine( "IsInfinity(3.0 / 0) == {0}.", Double::IsInfinity( 3.0 / zero ) ? (String^)"true" : "false" );
``````
``````// This will return "true".
Console.WriteLine("IsInfinity(3.0 / 0) == {0}.", Double.IsInfinity(3.0 / 0) ? "true" : "false");
``````
``````// This will return "true".
printfn \$"IsInfinity(3.0 / 0) = %b{Double.IsInfinity(3. / 0.)}."
``````
``````' This will return "True".
Console.Write("IsInfinity(3.0 / 0) = ")
If Double.IsPositiveInfinity(3 / 0) Then
Console.WriteLine("True.")
Else
Console.WriteLine("False.")
End If
``````

## Remarks

Floating-point operations return PositiveInfinity or NegativeInfinity to signal an overflow condition.