RE: [ros-dev] gcc problem or not

[Danny Smith]

>   -----Original Message-----
>  From: ros-dev-bounces(a)reactos.com 
>  [mailto:[e-mail]] On Behalf Of Thomas Weidenmueller
>  Sent: Wednesday, May 04, 2005 7:16 AM
>  To: ReactOS Development List
>  Subject: Re: [ros-dev] gcc problem or not
>  
>  
>  Hartmut Birr wrote:
> >   Hi,
> >  
> >  I was always the opinion  that the examination of a test condition 
> >  stops if the result can not change again. A test condition  
>  like this:
> >   
> >  if (pointer == NULL || pointer->member == 0)
> >  
> >  should never access pointer->member if pointer is zero.  
>  Compared with 
> >   the code above, it is possible that gcc build the
> > result from the 
> >  right side of the OR statement. This may hit a page fault.  
>  Is this a 
> >   bug in gcc? 
>  
>  It should definitely not dereference if it's NULL. The 
>  conditions should 
>  be checked from left to right in this case, no matter how much was 
>  optimized.
>   
To be safe, you might also check
BadReadPtr(pointer,sizeof(struct_pointed_to)).  The pointer may be
undefined, rather than NULL.

Danny

>   Thomas
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