Initializer

init(nan:signaling:)

Creates a NaN (“not a number”) value with the specified payload.

Declaration

init(nan payload: Double.RawSignificand, signaling: Bool)

Parameters

payload: The payload to use for the new NaN value.
signaling: Pass true to create a signaling NaN or false to create a quiet NaN.

Discussion

NaN values compare not equal to every value, including themselves. Most operations with a NaN operand produce a NaN result. Don’t use the equal-to operator (==) to test whether a value is NaN. Instead, use the value’s isNaN property.

let x = Double(nan: 0, signaling: false)
print(x == .nan)
// Prints "false"
print(x.isNaN)
// Prints "true"

See Also

Working with Binary Representation

var bitPattern: UInt64

The bit pattern of the value’s encoding.

var significandBitPattern: UInt64

The raw encoding of the value’s significand field.

var significandWidth: Int

The number of bits required to represent the value’s significand.

var exponentBitPattern: UInt

The raw encoding of the value’s exponent field.

static var significandBitCount: Int

The available number of fractional significand bits.

static var exponentBitCount: Int

The number of bits used to represent the type’s exponent.

static var radix: Int

The radix, or base of exponentiation, for this floating-point type.

init(bitPattern: UInt64)

Creates a new value with the given bit pattern.

init(sign: FloatingPointSign, exponentBitPattern: UInt, significandBitPattern: UInt64)

Creates a new instance from the specified sign and bit patterns.

typealias Double.Exponent

A type that can represent any written exponent.

typealias Double.RawSignificand

A type that represents the encoded significand of a value.