[Overview][Constants][Types][Classes][Procedures and functions][Variables][Index] | Reference for unit 'sysutils' (#rtl)

# TDoubleHelper

[Properties (by Name)] [Methods (by Name)] [Events (by Name)]

Helper for Double floating point type

## Declaration

Source position: syshelph.inc line 263

`type TDoubleHelper = type helper`
`public`
`Const`
`Epsilon = Epsilon; = 4.9406564584124654418e-324` |  | Precision for this floating point type
`MaxValue = MaxValue; = 1.7976931348623157081e+308` |  | Largest possible value for the Double floating point type
`MinValue = MinValue; = - 1.7976931348623157081e+308` |  | Smallest (negative) possible value for the Double floating point type
`PositiveInfinity = PositiveInfinity; = 1.0 / 0.0` |  | Positive infinity as represented by a Double floating point type
`NegativeInfinity = NegativeInfinity; = (- 1.0) / (0.0)` |  | Negative infinity as represented by a Double floating point type
`NaN = NaN; = 0.0 / 0.0` |  | Representation of NaN (Not a Number)
`class function IsInfinity();` |  | Check whether a value is positive or negative infinity.
`class function IsNan();` |  | Check whether a value equals NaN.
`class function IsNegativeInfinity();` |  | Check whether a value is negative infinity.
`class function IsPositiveInfinity();` |  | Check whether a value is positive infinity.
`class function Parse();` |  | Convert a string to a floating point value
`class function Size;` |  | Size (in bytes) of a Double-sized floating point value.
`class function ToString();` |  | Convert a Double-sized floating point value to a string
`class function TryParse();` |  | Try to convert a string to a Double-sized floating point value.
`procedure BuildUp();` |  | Build a Double-sized floating point from its composing parts
`function Exponent;` |  | Exponent of the floating-point value
`function Fraction;` |  | Fraction of the floating-point value
`function Mantissa;` |  | Mantissa of the floating-point
`function SpecialType;` |  | Return the type of the Double-sized floating point value
`property Bytes []: Byte; [rw]` |  | Indexed access to the individual bytes of the floating point value
`property Words []: Word; [rw]` |  | Indexed access to the words that make up the floating point value
`property Sign: Boolean; [rw]` |  | Sign of the floating point value
`property Exp: QWord; [rw]` |  | The bit pattern of the exponent as stored in memory.
`property Frac: QWord; [rw]` |  | Bitpattern that makes up the fractional part.
`end;`

## Inheritance

`TDoubleHelper` |  | Helper for Double floating point type

## Description

TDoubleHelper is the helper type for the Double-sized floating point type. It contains some conversion methods, as well as access to the low-level structure of the floating-point representation of a Double.

## See also

TDoubleHelper |  | Helper for Double floating point type
TExtendedHelper |  | Helper for Extended floating point type