On Thu, 8 Jul 2004 21:04:33 +0200 Tilman Sauerbeck <[EMAIL PROTECTED]>
babbled:

> > > [snip]
> > > Yeah, I'm aware of that. I'd only want to suppress the "handle already
> > > freed" messages, since they can only occur on ONE occasion with the Ruby
> > > bindings and I know it's safe to ignore these. I think :))
> > 
> > not really - it knows its already freed because the first 4 bytes (int)
> > contain a magic sequence. it's highly unlikely to find this sequence (it's
> > not a common number) and so your chances of a mis-detection are like 1 in 4
> > billion.
> > 
> > the PROBLEM is that it needs to read these 4 bytes - what if the object is
> > freed and libc has sbrk()'d the process size back down (not common - but
> > possible and it does happen when enough of the heap frees up at the top).
> > now those 4 bytes of magic check are not even within your processes memory
> > space - so the CHECK will cause a segv (as would any other attempt to access
> > the object). so in this case the app has not been saved. as i said - i didnt
> > check pointer values to see if they are within memory space of the process.
> > i actually dont know of a portable way of finding out what the memory space
> > is (easily) and tracking it(easily). so in this case you'd segv, and the
> > warnings are a sign that there is a possible segv there... :)
> 
> /me slaps forehead
> 
> Wow, I finally got what you meant, of couse you're right ;)
> No idea why I thought this was safe o_O

heheheheheh :) glad to be of service :) i guess it WOULD be good if i did have
checks to check for memory space too - then it would be possible to avoid segv's
and you'd be right - but... at this stage i don't REALLY know how to do that
(simply and portably) so there still is a segv possibility. ALSO remember that
it WOULD be possible to compile the EFL libs WITHOUT the checking (eg:
production environment where u have tested and checked everything so to gain
some speed you remove the checks) 

:)

-- 
------------- Codito, ergo sum - "I code, therefore I am" --------------
The Rasterman (Carsten Haitzler)    [EMAIL PROTECTED]
熊耳 - 車君 (数田)                  [EMAIL PROTECTED]
Tokyo, Japan (東京 日本)


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