Re: [Boost-users] [multi-index] dereferencing the end iterator

From: Ovanes Markarian (om_boost_at_[hidden])
Date: 2007-11-20 13:41:33

Joaquin,

but you could use an assert in the debug version? That would be of great
help.

I did not call modify(view.end(), ...). But my iterator was invalid, which I
wrongly initialized before. The call is just a further test to find out why
I got the wrong object instance in the modifier.

In this case to produce an assertion failure is probably of great help to
the developer.

Many thanks,
Ovanes

On 11/20/07, "JOAQUIN LOPEZ MU?Z" <joaquin_at_[hidden]> wrote:
>
> ----- Mensaje original -----
> De: Ovanes Markarian <om_boost_at_[hidden]>
> Fecha: Martes, Noviembre 20, 2007 4:57 pm
> Asunto: [Boost-users] [multi-index] dereferencing the end iterator
> Para: boost-users_at_[hidden]
>
> > Hello Joaquín,
> >
> > today I faced some problem, when debugging the code.
> [...]
> > When created a view for vx_hash tag and going to change the
> > invalid iteratorlike view.end(). Dereferencing view.end() fails
> > as awaited, but this code which calls my TypeModifier:
> >
> > view.modify(view.end(), my_modifier);
> >
> > This will result in my_modifier call with dereferenced iterator,
> which
> > contains badly initialized object.
> [...]
>
> Calling modify(end(),...) is illegal just as dereferencing
> end() is, but that does not mean that you can expect a crash when
> doing so: as you're invoking undefined behavior anything can
> happen.
>
> If you want to make sure that these illegal operations are
> properly detected and reported in a predictable way, take a
> look at Boost.MultiIndex safe mode:
>
> http://boost.org/libs/multi_index/doc/tutorial/debug.html#safe_mode
>
> (Don't forget to turn it off in release mode). Hope this helps,