SystemInt64

System.Int64 is a value type in the .NET framework that represents a 64-bit signed integer. It is the canonical type behind the C# keyword long and is defined in the System namespace as part of the primitive numeric types.

The type uses 8 bytes of storage and its range runs from -9,223,372,036,854,775,808 to 9,223,372,036,854,775,807. It is a two’s complement integer, which means negative numbers are represented in the standard signed format. As a value type, System.Int64 is stored inline or on the stack, and when boxed it becomes an object reference.

Key members and behavior include MinValue and MaxValue, along with methods such as CompareTo, Equals, GetHashCode, and ToString. It also provides static parsing helpers like Parse and TryParse for converting between strings and 64-bit values. System.Int64 implements several interfaces, including IComparable<long>, IEquatable<long>, IFormattable, and IConvertible, enabling a range of comparisons, formatting options, and conversions to other types.

Usage and semantics: System.Int64 is used when a 64-bit range is required, such as counting large quantities, representing timestamps (ticks), or handling big file sizes. In C# and other .NET languages, the alias long is commonly used. Arithmetic follows standard integer rules; overflow can wrap in an unchecked context and can throw an OverflowException in a checked context.

See also: System.UInt64, the unsigned 64-bit counterpart; parsing, formatting, and conversions to other numeric types. System.Int64 is a fundamental building block in .NET for high-range integer values.