The primitive type constructor for creating new C union types. Like C struct types, union types are new primitive types with no conversion functions associated. Unions are always treated like structs.

Creates a union type whose Racket representation is a union that works with union-ref and union-set!. The union is not copied; the Racket representation is backed by the underlying C representation.

Returns #t if v is a Racket representation of a C value via _union, #f otherwise.

Extracts a variant from a union.

Sets a variant in a union..

Extracts the pointer for a union’s storage.