Subject: IDL 6.0 patch for LOGICAL_AND and LOGICAL_OR
From: RSI E-mail Support <support@rsinc.com>
Date: Wed, 25 Feb 2004 17:09:54 -0700
To: "'ewbethel@lbl.gov'" <ewbethel@lbl.gov>

Dear Wes,

We are writing to alert you about an upcoming patch for IDL 6.0.

Last week, a customer reported a bug involving the LOGICAL_AND and
LOGICAL_OR functions introduced in IDL 6.0. If either operand is an array,
these functions may, under some conditions, quietly produce incorrect
results. This flaw does not occur if both operands are scalar, or single
element arrays. We believe that there is little or no user code affected by
this problem, because these functions are too new to have been used widely,
and because the scalar operand form is probably more common than the array
form.

Normally, flaws in IDL are corrected in the next release. However, we are
especially concerned about this one because these functions implement basic
logical operations, and might lead code using them to produce reasonable
looking, but incorrect, results. Despite our opinion that these routines are
not yet in widespread use, we have decided to err on the side of caution.
RSI will be issuing a patch for IDL 6.0 shortly that contains a fix for
LOGICAL_AND and LOGICAL_OR.  The patch will be focused on this particular
fix in the interest of making it available quickly without delaying the
release of IDL 6.1, which is currently scheduled for release this summer.

We will send out another announcement as soon as the patch is available.
Please feel free to contact us if you have any questions.

Thank you,
RSI Technical Support