# Real64 Data Type

Holds signed 64-bit (8-byte) IEEE floating-point values in the range −1.79769313486231570E+308 to −4.94065645841246544E−324 for negative values and 4.94065645841246544E−324 to 1.79769313486231570E+308 for positive values.

## Instructions

`Precision`- Be aware that floating-point data types are incapable of representing many values exactly. Operations such as comparisons can produce unexpected results. See Troubleshooting Data Types for more information.
`Space efficiency`- You can use
`Real64`in situations where the greater precision of`Real128`is unnecessary. In some cases, the ViviFire runtime may be able to pack your data more efficiently and reduce memory consumption. `Default value`- When you declare a variable of type
`Real64`and leave it uninitialized,, its value defaults to zero (0.0). `Coercion``Real64`widens to`Real`or`Real128`without any risk of overflow.`Trailing zeros`- The floating-point data types have no internal means of representing trailing 0 characters following the decimal point. This means that numbers such as 1.4200 and 1.42 represent the same value. If you must display trailing zeros, the number will need to be formatted.
`Type characters``Real64`has no type characters.

## Shared methods and properties

`Real64.Bits As UInt`

- Returns the number of available bits. This is always 64.
`Real64.Epsilon As Real64`

- Returns the smallest difference between two values.
`Real64.IsNaN(x As Real64) As Boolean`

- Returns true if the value of
`x`is not a number. Division by zero can cause this result. `Real64.Max As Real64`

- Returns the maximum positive value.
`Real64.Min As Real64`

- Returns the minimum positive value.

## Examples

```
Dim foo As Real64
```