bugGNU Common Lisp - Bugs: bug #47404, some comparisons with float...


bug #47404: some comparisons with float not-a-number return T

Submitted by:  Robert Dodier <robert_dodier1>
Submitted on:  Mon 14 Mar 2016 03:10:00 AM UTC  
Category:  None Severity:  3 - Normal
Item Group:  None Status:  None
Privacy:  Public Assigned to:  None
Open/Closed:  Open

Add a New Comment (Rich Markup)

You are not logged in

Please log in, so followups can be emailed to you.


Mon 14 Mar 2016 03:13:50 AM UTC, comment #1: 

Also, I note that not-a-number is displayed as #<-nan> as if it were negative. I am guessing that NaN will be displayed correctly (without the minus sign) when the numeric comparison bug is fixed.

Robert Dodier <robert_dodier1>
Mon 14 Mar 2016 03:10:00 AM UTC, original submission:  

Numerica comparisons with float not-a-number should always return NIL. But GCL appears to consider NaN to be less than all floats, including itself.

Example with doubles shown here. Same behavior with single floats.

I'm working on Ubuntu 14.04.

$ gcl
GCL (GNU Common Lisp)  2.6.12 ANSI    Aug 12 2015 09:36:50
Source License: LGPL(gcl,gmp), GPL(unexec,bfd,xgcl)
Binary License:  GPL due to GPL'ed components: (XGCL READLINE UNEXEC)
Modifications of this banner must retain notice of a compatible license
Dedicated to the memory of W. Schelter

Use (help) to get some basic information on how to use GCL.
Temporary directory for compiler files set to /tmp/

>(defvar x 1d300)


>(defvar i (* x x))


>(defvar n (- i i))


>(setq si:*print-nans* t)






>(every #'(lambda (a) (< n a)) (list n i (- i) 1 0 -1 1e7 -3d5))



Robert Dodier <robert_dodier1>


(Note: upload size limit is set to 16384 kB, after insertion of the required escape characters.)

Attach Files:

No files currently attached


Depends on the following items: None found

Items that depend on this one: None found


Carbon-Copy List
  • -email is unavailable- added by robert_dodier1 (Submitted the item)

    Do you think this task is very important?
    If so, you can add your encouragement to it.
    This task has 0 encouragements so far.

    Only logged-in users can vote.




    No changes have been made to this item

    Back to the top

    Powered by Savane 3.6