Represents the smallest positive Double value that is greater than zero. This field is constant.
Assembly: mscorlib (in mscorlib.dll)
The value of the property reflects the smallest positive Double value that is significant in numeric operations or comparisons when the value of the Double instance is zero. For example, the following code shows that zero and are considered to be unequal values, whereas zero and half the value of are considered to be equal.
More precisely, the floating point format consists of a sign, a 52-bit mantissa or significand, and an 11-bit exponent. As the following example shows, zero has an exponent of -1022 and a mantissa of 0. has an exponent of -1022 and a mantissa of 1. This means that is the smallest positive Double value greater than zero and represents the smallest possible value and the smallest possible increment for a Double whose exponent is -1022.
The value of the property is not equivalent to machine epsilon, which represents the upper bound of the relative error due to rounding in floating-point arithmetic.
The value of this constant is 4.94065645841247e-324.
Two apparently equivalent floating-point numbers might not compare equal because of differences in their least significant digits. For example, the C# expression, (double)1/3 == (double)0.33333, does not compare equal because the division operation on the left side has maximum precision while the constant on the right side is precise only to the specified digits. If you create a custom algorithm that determines whether two floating-point numbers can be considered equal, we do not recommend that you base your algorithm on the value of the constant to establish the acceptable absolute margin of difference for the two values to be considered equal. (Typically, that margin of difference is many times greater than .) For information about comparing two double-precision floating-point values, see Double and Equals(Double).
On ARM systems, the value of the constant is too small to be detected, so it equates to zero. You can define an alternative epsilon value that equals 2.2250738585072014E-308 instead.
.NET FrameworkSupported in: 4.5.1, 4.5, 4, 3.5, 3.0, 2.0, 1.1, 1.0
.NET Framework Client ProfileSupported in: 4, 3.5 SP1
Portable Class LibrarySupported in: Portable Class Library
.NET for Windows Store appsSupported in: Windows 8
.NET for Windows Phone appsSupported in: Windows Phone 8.1, Windows Phone 8, Silverlight 8.1
Windows Phone 8.1, Windows Phone 8, Windows 8.1, Windows Server 2012 R2, Windows 8, Windows Server 2012, Windows 7, Windows Vista SP2, Windows Server 2008 (Server Core Role not supported), Windows Server 2008 R2 (Server Core Role supported with SP1 or later; Itanium not supported)
The .NET Framework does not support all versions of every platform. For a list of the supported versions, see .NET Framework System Requirements.