From ...
From: Erik Naggum <erik@naggum.no>
Subject: Re: Does LISP have a "union" construct?
Date: 1998/12/03
Message-ID: <3121647269687464@naggum.no>#1/1
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* joswig@lavielle.com (Rainer Joswig)
| Certain implementations may signal an error when
| you want to create such an displaced array.

  from my reading of the standard, implementations are required to do this
  only for safe code.  "safe code" means a prevailing (optimize (safety 3))
  declaration.

  at least under Allegro CL, an (optimize (safety 0)) declaration turns off
  every check there is, but you are definitely on your own if you do that.

#:Erik
-- 
  The Microsoft Dating Program -- where do you want to crash tonight?