This documentation is archived and is not being maintained.

BitConverter.DoubleToInt64Bits Method

Converts the specified double-precision floating point number to a 64-bit signed integer.

Namespace:  System
Assembly:  mscorlib (in mscorlib.dll)

public static long DoubleToInt64Bits(
	double value


Type: System.Double
The number to convert.

Return Value

Type: System.Int64
A 64-bit signed integer whose value is equivalent to value.

The order of bits in the integer returned by the DoubleToInt64Bits method depends on whether the computer architecture is little-endian or big-endian.

The following code example converts the bit patterns of several Double values to Int64 values with the DoubleToInt64Bits method.

// Example of the BitConverter.DoubleToInt64Bits method.
using System;

class DoubleToInt64BitsDemo
    const string formatter = "{0,25:E16}{1,23:X16}";

    // Reinterpret the double argument as a long.
    public static void DoubleToLongBits( double argument )
        long longValue;
        longValue = BitConverter.DoubleToInt64Bits( argument );

        // Display the resulting long in hexadecimal.
        Console.WriteLine( formatter, argument, longValue );

    public static void Main( )
            "This example of the BitConverter.DoubleToInt64Bits( " +
            "double ) \nmethod generates the following output.\n" );
        Console.WriteLine( formatter, "double argument", 
            "hexadecimal value" );
        Console.WriteLine( formatter, "---------------", 
            "-----------------" );

        // Convert double values and display the results.
        DoubleToLongBits( 1.0 );
        DoubleToLongBits( 15.0 );
        DoubleToLongBits( 255.0 );
        DoubleToLongBits( 4294967295.0 );
        DoubleToLongBits( 0.00390625 );
        DoubleToLongBits( 0.00000000023283064365386962890625 );
        DoubleToLongBits( 1.234567890123E-300 );
        DoubleToLongBits( 1.23456789012345E-150 );
        DoubleToLongBits( 1.2345678901234565 );
        DoubleToLongBits( 1.2345678901234567 );
        DoubleToLongBits( 1.2345678901234569 );
        DoubleToLongBits( 1.23456789012345678E+150 );
        DoubleToLongBits( 1.234567890123456789E+300 );
        DoubleToLongBits( double.MinValue );
        DoubleToLongBits( double.MaxValue );
        DoubleToLongBits( double.Epsilon );
        DoubleToLongBits( double.NaN );
        DoubleToLongBits( double.NegativeInfinity );
        DoubleToLongBits( double.PositiveInfinity );

This example of the BitConverter.DoubleToInt64Bits( double )
method generates the following output.

          double argument      hexadecimal value
          ---------------      -----------------
  1.0000000000000000E+000       3FF0000000000000
  1.5000000000000000E+001       402E000000000000
  2.5500000000000000E+002       406FE00000000000
  4.2949672950000000E+009       41EFFFFFFFE00000
  3.9062500000000000E-003       3F70000000000000
  2.3283064365386963E-010       3DF0000000000000
  1.2345678901230000E-300       01AA74FE1C1E7E45
  1.2345678901234500E-150       20D02A36586DB4BB
  1.2345678901234565E+000       3FF3C0CA428C59FA
  1.2345678901234567E+000       3FF3C0CA428C59FB
  1.2345678901234569E+000       3FF3C0CA428C59FC
  1.2345678901234569E+150       5F182344CD3CDF9F
  1.2345678901234569E+300       7E3D7EE8BCBBD352
 -1.7976931348623157E+308       FFEFFFFFFFFFFFFF
  1.7976931348623157E+308       7FEFFFFFFFFFFFFF
  4.9406564584124654E-324       0000000000000001
                      NaN       FFF8000000000000
                -Infinity       FFF0000000000000
                 Infinity       7FF0000000000000

.NET Framework

Supported in: 4, 3.5, 3.0, 2.0, 1.1, 1.0

.NET Framework Client Profile

Supported in: 4, 3.5 SP1

Windows 7, Windows Vista SP1 or later, Windows XP SP3, Windows XP SP2 x64 Edition, Windows Server 2008 (Server Core not supported), Windows Server 2008 R2 (Server Core supported with SP1 or later), Windows Server 2003 SP2

The .NET Framework does not support all versions of every platform. For a list of the supported versions, see .NET Framework System Requirements.