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*unbound*

*unbound*

type: system constant
location: built-in
source file: xlinit.c  and  xlsym.c
Common LISP compatible: no
supported on: all machines

SYNTAX

*unbound*

DESCRIPTION

*UNBOUND* is a system constant that is used to indicate when a symbol has no value. *UNBOUND* is set to the value *UNBOUND*. This means that the system thinks the symbol *UNBOUND* has no value.

EXAMPLES

*unbound*                               ; error: unbound variable
(setq a 5)                              ; returns 5
a                                       ; returns 5
(setq a '*unbound*)                     ; returns *UNBOUND*
a                                       ; error: unbound variable


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