OpenEuphoria

RE: Invalid Page Fault and Safe.e

• Posted by Virtual B <behaviorself at netzero.net> Apr 17, 2001
• 395 views

Robert Craig wrote:
> Virtual B. writes:
> > This is not just a problem with my program either.  
> > I've tried it with a lot of the programs that come with 
> > Win32Lib and get the same results.  
> 
> Safe.e can't be used with Win32Lib.
> 
> A long time ago safe.e was able to catch subtle 
> memory corruption bugs in Win32Lib-based programs,
> but that is no longer possible for two reasons:
> 
> 1. The implementors of Win32Lib decided not to use
> Euphoria's allocate() and free() but instead to
> develop their own heap routines using direct calls to 
> WIN32 API routines. The reasons for this are not clear to me.
> 
> 2. There are some places where Win32Lib
> picks up the address of a block of memory from a call
> to a C routine. They would have to call register_block()
> and unregister_block() in safe.e to track this.
> I'm not sure how much work would be involved here.
> I've recently added a switch to safe.e that allows you
> to not bother registering any external blocks, in exchange for
> having a much weaker check on memory. In this case it 
> only checks the "gutter" areas just before and just after
> each allocated block for corruption. Addresses that are 
> far removed from any allocated block would be 
> assumed safe. However this requires that
> allocate() and free() actually be used (point #1).
> 
> Regards,
>    Rob Craig
>    Rapid Deployment Software
>    http://www.RapidEuphoria.com
> 
> 
> 
Thanks Rob.  I still don't know what's causing the occasional invalid 
page fault, but at least I know I can't use Safe.e with Win32Lib apps.  
I thought something was seriously wrong on this end.  I appreciate the 
input.

Virtual B