Structs and Unions in DTrace

Collections of related variables can be grouped together into composite data objects called structs and unions. You can define these objects in D by creating new type definitions for them. You can use your new types for any D variables, including associative array values. This section explores the syntax and semantics for creating and manipulating these composite types and the D operators that interact with them. The syntax for structs and unions is illustrated using several example programs that demonstrate the use of the DTrace function boundary tracing (fbt) and pid providers.