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defcenum

defcenum

Syntax

Macro: defcenum name-and-options &body enum-list

enum-list ::= [docstring] { keyword | (keyword value) }* name-and-options ::= name | (name &optional (base-type :int))

Arguments and Values

name

The name of the new enum type.

docstring

A documentation string, ignored.

base-type

A symbol denoting a foreign type.

keyword

A keyword symbol.

value

An index value for a keyword.

Description

The defcenum macro is used to define foreign types that map keyword symbols to integer values, similar to the C enum type.

If value is omitted its value will either be 0, if it’s the first entry, or it it will continue the progression from the last specified value.

Keywords will be automatically converted to values and vice-versa when being passed as arguments to or returned from foreign functions, respectively. The same applies to any other situations where an object of an enum type is expected.

Types defined with defcenum canonicalize to base-type which is :int by default.

Examples

  (defcenum boolean
    :no
    :yes)
   
  CFFI> (foreign-enum-value 'boolean :no)
  ⇒ 0
  (defcenum numbers
    (:one 1)
    :two
    (:four 4))
   
  CFFI> (foreign-enum-keyword 'numbers 2)
  ⇒ :TWO

See Also

foreign-enum-value
foreign-enum-keyword