5 Function and Macro Reference

define-c-union

Macro

Summary

Defines an FLI union type corresponding to the Cunion type.

Package

fli

Signature

define-c-union name &rest slot-descriptions => list

slot-descriptions ::= {slot-name | (slot-name slot-type)}*

Arguments

name: The name of the new union type descriptor.
slot-descriptions: A sequence of symbols, possibly with type descriptions, naming the slots of the union.
slot-name: A symbol naming the slot.
slot-type: The FLI type of the slot.

Values

list: The list(:unionname).

Description

The macrodefine-c-union is used to define an FLI union type specifier, which corresponds to the Cunion type. It is a convenience function, as a union type could also be defined usingdefine-foreign-type.

A union is an aggregate type, or collection, of other FLI types. The types contained in a union are referred to as slots, and can be accessed using theforeign-slot-type andforeign-slot-value functions.

Example

In the following example a union is defined usingdefine-c-union, and the corresponding C code is given.

(fli:define-c-union a-point (x :int)
                            (color :byte)
                            (ident :char))

union a-point {
  int x;
  byte color;
  char ident;
};

See Also
: define-c-enum
: define-c-struct
: define-c-typedef
: define-foreign-type