Re: [Boost-users] [variant] 'which' out of range assertion

Subject: Re: [Boost-users] [variant] 'which' out of range assertion
From: Daniel Bradburn (moagstar_at_[hidden])
Date: 2012-02-22 15:37:39

I don't see anything in that thread that suggests this is a bug. I think
Steve's statement that the limitation can be worked around by using
make_variant_over is no longer valid, since some pretty crucial variant
visitation code uses preprocessor metaprogramming and
BOOST_VARIANT_LIMIT_SIZE is central to this (take a look at
BOOST_VARIANT_VISITATION_UNROLLING_LIMIT in visitation_impl.hpp). Perhaps
this is something new since that thread (2008) - however I don't see
anything in the release notes from 145 to 147 which would suggest that
something changed here (145 is the version I upgraded from when this last
worked for me). It may be possible to just
define BOOST_VARIANT_VISITATION_UNROLLING_LIMIT and get the desired effect.

2012/2/22 Igor R <boost.lists_at_[hidden]>

> > Although it affects the variadic form of the mpl containers, the limit
> for
> > variant types is set from the BOOST_MPL_LIMIT_LIST_SIZE macro.
>
>
> Take a look at this thread:
> http://lists.boost.org/boost-users/2008/05/36488.php
>
> So, despite the workaround you found, it seems to be a bug.
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