ToC DocOverview CGDoc RelNotes Index PermutedIndex
Allegro CL version 7.0
Home Previous Up Next Table of Contents Index
  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.

Home Previous Up Next Table of Contents Index
© Franz Inc. 1998-2002 - File last updated 6-21-2002