[Boost-users] [intrusive] unordered_set::iterator_to

Subject: [Boost-users] [intrusive] unordered_set::iterator_to
From: Paul Rose (paul.d.rose_at_[hidden])
Date: 2011-02-10 13:58:11

Hi,

I'm getting compile errors trying to use iterator_to() on an unordered_set
when given a const reference (and returning a const_iterator).

It works fine for me with ordered set.

I am able to reproduce this error by adding the following two lines:

   MyClass const &cr = values[0];
   base_set.iterator_to(cr);

to the bottom of the Example code (just before the return 0 from main) for
unordered_set at:

http://www.boost.org/doc/libs/1_45_0/doc/html/intrusive/unordered_set_unordered_multiset.html#intrusive.unordered_set_unordered_multiset.unordered_set_unordered_multiset_example

The error is:
/opt/boost/include/boost-1_38/boost/intrusive/hashtable.hpp: In member
function
‘boost::intrusive::detail::hashtable_iterator<boost::intrusive::hashtable_impl<Config>,
true> boost::intrusive::hashtable_impl<Config>::iterator_to(typename
std::iterator_traits<typename
boost::intrusive::detail::eval_if_c<boost::intrusive::hashtable_impl<Config>::external_value_traits,
boost::intrusive::detail::eval_value_traits<typename Config::value_traits>,
boost::intrusive::detail::identity<typename Config::value_traits>
>::type::const_pointer>::reference) const [with Config =
boost::intrusive::detail::usetopt<boost::intrusive::detail::base_hook_traits<MyClass,
boost::intrusive::slist_node_traits<void*>, safe_link,
boost::intrusive::default_tag, 4>, boost::hash<MyClass>,
std::equal_to<MyClass>, long unsigned int,
boost::intrusive::detail::bucket_traits_impl<boost::intrusive::detail::get_slist_impl<boost::intrusive::slist_node_traits<void*>
>::type>, 3ul>]’:

/opt/boost/include/boost-1_38/boost/intrusive/unordered_set.hpp:733:
instantiated from ‘typename
boost::intrusive::hashtable_impl<Config>::const_iterator
boost::intrusive::unordered_set_impl<Config>::iterator_to(typename
boost::intrusive::hashtable_impl<Config>::const_reference) const [with
Config =
boost::intrusive::detail::usetopt<boost::intrusive::detail::base_hook_traits<MyClass,
boost::intrusive::slist_node_traits<void*>, safe_link,
boost::intrusive::default_tag, 4>, boost::hash<MyClass>,
std::equal_to<MyClass>, long unsigned int,
boost::intrusive::detail::bucket_traits_impl<boost::intrusive::detail::get_slist_impl<boost::intrusive::slist_node_traits<void*>
>::type>, 3ul>]’

example.cpp:82:   instantiated from here
/opt/boost/include/boost-1_38/boost/intrusive/hashtable.hpp:1682: error: no
matching function for call to
‘boost::intrusive::detail::hashtable_iterator<boost::intrusive::hashtable_impl<boost::intrusive::detail::usetopt<boost::intrusive::detail::base_hook_traits<MyClass,
boost::intrusive::slist_node_traits<void*>, safe_link,
boost::intrusive::default_tag, 4>, boost::hash<MyClass>,
std::equal_to<MyClass>, long unsigned int,
boost::intrusive::detail::bucket_traits_impl<boost::intrusive::detail::get_slist_impl<boost::intrusive::slist_node_traits<void*>
>::type>, 3ul> >,
true>::hashtable_iterator(boost::intrusive::slist_iterator<boost::intrusive::slist_impl<boost::intrusive::slistopt<boost::intrusive::trivial_value_traits<boost::intrusive::slist_node_traits<void*>,
normal_link>, long unsigned int, false, false, false> >, true>, const
boost::intrusive::hashtable_impl<boost::intrusive::detail::usetopt<boost::intrusive::detail::base_hook_traits<MyClass,
boost::intrusive::slist_node_traits<void*>, safe_link,
boost::intrusive::default_tag, 4>, boost::hash<MyClass>,
std::equal_to<MyClass>, long unsigned int,
boost::intrusive::detail::bucket_traits_impl<boost::intrusive::detail::get_slist_impl<boost::intrusive::slist_node_traits<void*>
>::type>, 3ul> >* const)’

I am using 1_38_0.  I have not yet tried 1_45_0, but I have gone through the
entire list of fixed bugs on the release notes between 1_38 and 1_45.

I'll try 1_45_0 in the next few days, just in case.

I am able to work around my issue by casting away const on my reference
before calling iterator_to and assigning the result back into a
const_iterator, so for me it is nothing more than an annoyance, but I
thought I'd bring it to your attention so it can be fixed in a future
release.

Thanks,
Paul Rose