[Multiindex] Const_mem_fun from base class
Hello, I get an error when I'm trying to use a const member function in a multi-index container, as a template parameter for indexed_by<>. This const member function comes from a base class, from which the class contained in the multiindex container is derived. The error is the following: /home/yardbird/documenti/work/prog/piranha/pyranha/Gsp/../../src/polynomial.h:41: error: could not convert template argument ‘&piranha::base_monomial_gmp_array<piranha::double_cf>::get_degree’ to ‘int (piranha::monomial_gmp_array<piranha::double_cf>::*)()const’ The member function is named "get_degree", and returns an integer. The base class is "base_monomial_gmp_array", the derived class is, unsurprisingly, "monomial_gmp_array". If I "lift" this function to the derived class, by re-defining it there, the problem disappears. I have a hunch that probably with some clever typedef or some static_cast wizardy this could be resolved, however my experiments have not resolved anything yet. Does anyone have an idea on how to proceed? Thanks in advance, Francesco Biscani.
Hi Francesco, ----- Mensaje original ----- De: Francesco Biscani <bluescarni@gmail.com> Fecha: Domingo, Mayo 20, 2007 3:13 pm Asunto: [Boost-users] [Multiindex] Const_mem_fun from base class Para: boost-users@lists.boost.org
Hello,
I get an error when I'm trying to use a const member function in a multi-index container, as a template parameter for indexed_by<>. This const member function comes from a base class, from which the class contained in the multiindex container is derived. The error is the following:
/home/yardbird/documenti/work/prog/piranha/pyranha/Gsp/../../src/ polynomial.h:41: error: could not convert template argument ‘&piranha::base_monomial_gmp_array<piranha::double_cf>::get_degree’ to ‘int (piranha::monomial_gmp_array<piranha::double_cf>::*)()const’ [...]
This is probably #1 B.MI-related FAQ as of the last few months :) Please read the following post where the issue is explained: http://lists.boost.org/boost-users/2006/12/24042.php To sum it up, you've got two options: 1. If you're already using Boost 1.34, use the following key extractor: const_mem_fun< base_monomial_gmp_array<double_cf>, int, &base_monomial_gmp_array<double_cf>::get_degree
2. If you have to stick to Boost 1.33.1, write up a custom key extractor. Does this help? Thanks for using Boost.MultiIndex, Joaquín M López Muñoz Telefónica, Investigación y Desarrollo
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"JOAQUIN LOPEZ MU?Z" -
Francesco Biscani