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

From: JOAQUIN LOPEZ MU?Z (joaquin_at_[hidden])
Date: 2007-11-20 13:27:43

----- 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,

Joaquín M López Muñoz
Telefónica, Investigación y Desarrollo