RAPL 3 - Reference Guide. - Phoenix Goucher

30 Data Types and Variables
Unions
Unions (like unions in C) are possible.
union
field_list
end union
Where field_list is a list of declarations which can include int, float, string[], cloc,
ploc, or a complex type like struct or union.
union
int a
float b
end union xxx
typedef omega union
int a
float b
end union
Unions are referenced like structures, but have one important difference. All of
the fields of a structure are located in distinct locations in memory, allowing all
fields of a structure to hold values at the same time. However, in unions, all
fields are located at the same memory location. Hence in variable xxx above,
writing into field a of the union also alters the value of field b. Unions are
typically used where a block of information may hold more than one kind of data.