RE: [boost] Re: boost::execution_monitor impl under windows

From: Alan.Griffiths_at_[hidden]
Date: 2003-10-02 02:56:19

> -----Original Message-----
> From: Alexander Terekhov [mailto:terekhov_at_[hidden]]
> Sent: 01 October 2003 19:33
> 
> as I 
> said, SEH exceptions are just ought to be "fully mapped" to the 
> standard C++ exceptions. 

That is a circular arguement - you are assuming the point you are trying to
establish.  (One possible reason this mapping might not be possible is that
SEH does not respect sequence points.)

While C++ exceptions might reasonably be presented as a specialisation of
SEH exceptions the converse isn't true.  (Aside from the unresolved question
over sequence points SEH exceptions can occur without a throw expression,
can be resumed, are not available on all platforms, ...)

> 
> [...]
> >   o by the runtime environment (which calls "unexpected"
> >     without *any* cleanup).  While the program as a whole
> >     is clearly broken in this case, this breaks cleanup
> >     guarantees that exist between the throw point and the
> >     top of the stack.  
> 
> ISO/IEC 14882:
> 
> "If no matching handler is found in a program, the function 
>  terminate() is called; whether or not the stack is unwound 
>  before this call to terminate() is implementation-defined"
> 

An implementation must document how it behaves and (admittedly only QOI)
some do it right.  I prefer this to requiring them to do it wrong.  In any
event this is not worth spending much time on - the program is broken.

-- 
Alan Griffiths
http://www.octopull.demon.co.uk/ 
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