1 Language Model
2 Syntactic Forms
3 Datatypes
4 Structures
5 Classes and Objects
6 Units
7 Contracts
8 Pattern Matching
9 Control Flow
10 Concurrency
11 Macros
12 Input and Output
13 Reflection and Security
14 Operating System
15 Memory Management
16 Running PLT Scheme
On this page:
Version: 4.0


3.17 Void and Undefined

The constant #<void> is returned by most forms and procedures that have a side-effect and no useful result. The constant #<undefined> is used as the initial value for letrec bindings.

(void? v)  void?

  v : any/c

Returns #t if v is the constant #<void>, #f otherwise.

(void v ...)  void?

  v : any/c

Returns the constant #<void>. Each v argument is ignored.