Re: [Boost-users] [multi index] combination with boos t::tuple

From: Joaquín Mª López Muñoz (joaquin_at_[hidden])
Date: 2007-01-23 06:21:41

Markus Werle ha escrito:

> Hi!
>
> Even for the more correct typedef I get lost:
>
>     typedef bm::multi_index_container
>     <data_t,
>      bm::indexed_by
>      <bm::sequenced<>,
>       bm::ordered_unique
>       <bm::const_mem_fun<data_t,
>          std::string const &,
>          &data_t::get<0> > > > > storage_t;
>
>
>
> this fails due to probably disallowed standard conversions
> (or a cobfused gcc-4.0.3): Cleaned up error message:

[...]

Hello Markus,

This particular problem of using tuple fields as key extractors is
discussed at the following thread:

http://lists.boost.org/boost-users/2005/12/16087.php

Please take a look at it and come back if anything's not clear:
summing it up, what you get will work when Boost 1.34 comes out
or if using a CVS snapshot, except that you have to write
data_t::inherited when declaring the extractor's base class:

bm::const_mem_fun<
  data_t::inherited,
  std::string const &,
  &data_t::get<0>
>

And the other solution is to write a user-defined extractor as
explained in the aforementioned thread.

HTH,

Joaquín M López Muñoz
Telefónica, Investigación y Desarrollo