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  ANSI Common Lisp   12 Numbers   12.2 Dictionary of Numbers

12.2.65 logtest Function

Syntax:
logtest integer-1 integer-2    generalized-boolean

Arguments and Values:
integer-1 - an integer.

integer-2 - an integer.

generalized-boolean - a generalized boolean.

Description:
Returns true if any of the bits designated by the 1's in integer-1 is 1 in integer-2; otherwise it is false. integer-1 and integer-2 are treated as if they were binary.

Negative integer-1 and integer-2 are treated as if they were represented in two's-complement binary.

Examples:
 (logtest 1 7)  true
 (logtest 1 2)  false
 (logtest -2 -1)  true
 (logtest 0 -1)  false

Exceptional Situations:
Should signal an error of type type-error if integer-1 is not an integer. Should signal an error of type type-error if integer-2 is not an integer.

Notes:
 (logtest x y) ==(not (zerop (logand x y)))

Allegro CL Implementation Details:
None.

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