RE: Compiler generated exceptions (Was: Re: AW: [boost] Exception specifications in smart_ptr.hpp)

From: Andy Sawyer (boost_at_[hidden])
Date: 2000-07-26 13:28:01

On 21 July 2000 19:58, Valentin Bonnard wrote:

> > I haven't seen any instructions yet, that 'undefined' 
> operations shall throw
> > exceptions. 
> 
> In MSVC it's what happens. (Not C++ exceptions, but some kind 
> of OS-specific C++-independant exceptions.)
> 
> The interaction in MSVC (or in an ideal world) with C++ ES 
> (exception specs) isn't very clear to me.
> 

 Actually what happens is that the OS "throws an exception"
(i.e. generates a fault). The OS allows the developer to write
a "fault handler", and the default handler in the MS RunTime
translates the OS exception into a C++ exception (you can, of
course, change this behaviour)
 So neither the original OS exception nor the C++ exception
are actually compiler generated in this circumstance.

> > Couldn't there be an option to detect them? Like:
> > 
> > T& operator *() const throw()
> > {
> > #if BOOST_DETECT_UNDEFINED_OPS
> >         if (v==NULL) throw undefined_behaviour();
> > #endif
> >         return *v;
> > }
> 

 You could, if you so desired, do exactly that by supplying
your own exception translator.

Regards,
 Andy
-- 
Andy Sawyer, Technical Director, Sufficiently Advanced Technology Ltd.
mailto:andys_at_[hidden]        ICQ:14417938        http://www.morebhp.com