XLISP *unbound*

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# *unbound*

Type: | - | system constant
Source: | - | xlinit.c, xlsym.c

## Syntax

*unbound*

## Description

The *unbound* system constant 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

See the *unbound* system constant in the XLISP 2.0 manual.

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Nyquist / XLISP 2.0 - Contents | Tutorials | Examples | Reference