Ultimate bug

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2 total messages Started by Art Shelest Fri, 19 Apr 1996 14:30

#2625

Author: Art Shelest
Date: Fri, 19 Apr 1996 14:30

18 lines
882 bytes

Below is the bug I got to fix last night (in someone else's code).
It's not the actual code, but you'll get the idea:

void* AllocMem( size_t cbMem )
{
   void* pMem = malloc( cbMem );

   if( pMem )
      memset( &pMem, 0, cbMem );  /* note & */

   return pMem;
}

I wonder if Lint would ever catch this one.
The net effect that this function would never return (to where it should 
return, anyway), ant took good 2 hours to find it in 200K+ lines of code.

    _Art.

Re: Ultimate bug

#2627

Author: Dan Pop
Date: Sat, 20 Apr 1996 18:21

29 lines
1305 bytes

In <4l881k$76k@solutions.solon.com> Artyom@kansmen.com (Art Shelest) writes:

>Below is the bug I got to fix last night (in someone else's code).
>It's not the actual code, but you'll get the idea:
>
>void* AllocMem( size_t cbMem )
>{
>   void* pMem = malloc( cbMem );
>
>   if( pMem )
>      memset( &pMem, 0, cbMem );  /* note & */
>
>   return pMem;
>}
>
>I wonder if Lint would ever catch this one.

Never.  Any kind of pointer (except function pointers and pointers to const
objects) is OK as the first argument of memset, which expects a void pointer.

Reading the programmer's mind and comparing it with programmer's code is
beyond the current state of the art in lint technology.

Dan
--
Dan Pop
CERN, CN Division
Email: danpop@mail.cern.ch 
Mail:  CERN - PPE, Bat. 31 R-004, CH-1211 Geneve 23, Switzerland

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