Re: [Boost-users] pointer to member function of multi_index

Subject: Re: [Boost-users] pointer to member function of multi_index
From: Sandeep Gupta (gupta.sandeep_at_[hidden])
Date: 2009-03-17 23:31:56

On Tue, Mar 17, 2009 at 7:57 PM, Steven Watanabe <watanabesj_at_[hidden]> wrote:
> AMDG
>
> Sandeep Gupta wrote:
>>
>> I am sure this is due to some trivial mistake; the statement to
>> create a pointer member function insert of multi_index container fails
>> in the following code:
>>
>>
>> typedef multi_index_container<
>>     std::pair<int,int>,
>>     indexed_by<
>>     ordered_unique<member<pair<int,int>, int, &pair<int, int>::first> >
>>     >
>>     > mic;
>>
>>
>> std::pair<mic_index::iterator, bool> (mic_index::*fn)(pair<int,int>) =
>> &mic_index::insert; //compile error
>>
>>
>> The error is due to mismatch in signature as given in the error:
>>
>> std::pair<boost::multi_index::detail::bidir_node_iterator<boost::multi_index::detail::ordered_index_node<boost::multi_index::detail::index_node_base<std::pair<int,
>> int>, ...
>>
>> std::pair<boost::multi_index::detail::bidir_node_iterator<boost::multi_index::detail::ordered_index_node<typename
>> SuperMeta::type::node_type> >, bool>...
>>
>> If need be I can post full error message. Appreciate any suggestions.
>>
>
> The signature is
> std::pair<mic_index::iterator, bool> (mic_index::*fn)(const pair<int,int>&);
>
> However, it is not usually a good idea to rely on the exact
> signature of library member functions.  For instance, the standard
> library allows member functions to have extra default arguments.
> In the case of multi_index, using a reference to const will not
> always work because multi_index uses call_traits.
>
> In Christ,
> Steven Watanabe
>

I see. So I take it that its  best to avoid creating function objects
or pointer to standard library member functions.

Thanks
sandeep