Subject: Re: nasty bug in bsearch() in b17.1 under Windows'95????
From: [email-masked] (Mumit Khan)

26 Mar 1997 19:55:06 -0800
Approved: [email-masked]
Distribution: cygnus
Message-ID: <[email-masked]>
Original-To: Jim Balter <[email-masked]>
Original-Cc: [email-masked]
In-Reply-To: Your message of "Tue, 25 Mar 1997 03:53:34 PST."
             <[email-masked]> 
Original-Sender: [email-masked]

Jim Balter <[email-masked]> writes:
> 
> The bsearch.c in newlib contains a quite explicit and quite erroneous
> comparison to the item one past the last range whenever the key isn't
> found.  Normally this is merely pointless extra work, but if the key is
> greater than the last element, then it is an out of bounds reference,
> just as you have discovered.  The "easiest" fix is to simply remove the
> lines
> 
>   if (compar (key, base) == 0)
>     return (_PTR) base;
> 

Exactly. Just looked at the source, and it's quite obvious. As you
mention, it also does an extra comparison for no reason whatsoever
in the other cases.

Here's the trivial patch, which took non-trivial number of hours
to find ;-) debugging f771 on a '95 box is no fun. 

*** bsearch.c.~1	Tue Mar 25 22:47:42 1997
--- bsearch.c	Tue Mar 25 22:47:46 1997
*************** _DEFUN (bsearch, (key, base, nmemb, size
*** 94,100 ****
      }
  
-   if (compar (key, base) == 0)
-     return (_PTR) base;
- 
    return NULL;
  }
--- 94,97 ----

Regards,
Mumit -- [email-masked]
http://www.xraylith.wisc.edu/~khan/
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