Continuing in the series sharing some of the information in the .NET Framework Standard Library Annotated Reference Vol 1 and .NET Framework Standard Library Annotated Reference Vol 2 with some information on DecimalConstantAttribute.
RJ (Rex Jaeschke)
The metadata does not directly support the representation of constants of type System.Decimal. As a result, in the code generated by the C# (and VB) compiler, they are stored as an
attribute using the type DecimalConstantAttribute. Consider the following C# code:
public class Test
private const decimal d = 12.3456m;
The relevant MSIL generated is
.field private static initonly valuetype [mscorlib]System.Decimal d
.custom instance void
uint8, uint8, uint32, uint32, uint32) = ( … hex bytes … )
This type is not intended to be used directly by programmers, but rather by compiler writers,
based on the programmer’s use of some language syntax (such as the keywords const
decimal in C#).
Note that it is expected that a future implementation of the CLI will support an alternate
representation of the decimal type, which has a much larger range, and a scale that exceeds
eight bits. As such, new constructors and methods are likely to be added to this type, as well as
This attribute has been a hot topic in ECMA discussions. A new IEEE 128-bit decimal
representation offers more range/precision (in the same number of bits!) than the current CLR
implementation. If CLR were to support this new IEEE decimal in the future, this attribute will
present a problem because the IEEE decimal’s scale is wider than the byte type of the
constructor’s scale parameter. It is likely that the parameter types of the constructor will be
widened and/or additional constructors added in a future release to make an IEEE decimal
implementation an option for a future CLR release.