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zerop

zerop

type: predicate function (subr)
location: built-in
source file: xlmath.c
Common LISP compatible: yes
supported on: all machines

SYNTAX

(zerop <expr> )
        <expr>          -       the numeric expression to check

DESCRIPTION

The ZEROP predicate checks to see if the number <expr> is zero. T is returned if the number is zero, NIL is returned otherwise. A bad argument type error is generated if the <expr> is not a numeric expression.

EXAMPLES

(zerop 0)                               ; returns T
(zerop 0.0)                             ; returns T
(zerop 99999.9)                         ; returns NIL
(zerop -0.000000000002)                 ; returns NIL
                                        ;
(zerop 'a)                              ; error: bad argument type
(setq a 0)                              ; set value of A to 0
(zerop a)                               ; returns T


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