c++ - クランはboost::signals2が好きではありませんか?

Question

Boost::Signals2 ライブラリを使用して、コードの一部からコンパイラエラーが発生し続けました。私がやろうとしていることを最小限の例に減らしました：

#include <boost/signals2.hpp>

int foo();

struct first_nonzero
{
    using result_type = int;

    template <typename It>
    result_type operator()(It first, It last) const
    {
    while(first != last)
    {
        if(*first != 0)
        {
            return *first;
        }
    }
    return 0;
    }
};

int foo()
{
    using signal = boost::signals2::signal<int (), first_nonzero>;
    signal s;
    return s();
}

このスニペットをコンパイルしようとすると

clang -o foo.o -c foo.cpp -std=c++11 -Weverything -Wno-c++98-compat

シグナルライブラリ自体に起因するように見えるテンプレート推定エラーが発生します。

In file included from foo.cpp:1:
In file included from /usr/include/boost/signals2.hpp:19:
In file included from /usr/include/boost/signals2/signal.hpp:38:
In file included from /usr/include/boost/signals2/variadic_signal.hpp:21:
/usr/include/boost/signals2/detail/variadic_slot_invoker.hpp:84:23: error: no matching function for call to 'get'
      return func(std::get<indices>(args)...);
                  ^~~~~~~~~~~~~~~~~
/usr/include/boost/signals2/detail/variadic_slot_invoker.hpp:78:18: note: in instantiation of function template specialization 'boost::signals2::detail::call_with_tuple_args<int>::m_invoke<int,
      boost::function<int ()>, 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, boost::tuples::null_type, boost::tuples::null_type, boost::tuples::null_type, boost::tuples::null_type, boost::tuples::null_type,
      boost::tuples::null_type, boost::tuples::null_type, boost::tuples::null_type, boost::tuples::null_type, boost::tuples::null_type>' requested here
      return m_invoke(resolver, func, indices_type(), args);
             ^
/usr/include/boost/signals2/detail/variadic_slot_invoker.hpp:120:18: note: in instantiation of function template specialization 'boost::signals2::detail::call_with_tuple_args<int>::operator()<boost::function<int
      ()>, boost::tuples::null_type, boost::tuples::null_type, boost::tuples::null_type, boost::tuples::null_type, boost::tuples::null_type, boost::tuples::null_type, boost::tuples::null_type,
      boost::tuples::null_type, boost::tuples::null_type, boost::tuples::null_type>' requested here
      return call_with_tuple_args<result_type>()(connectionBody->slot.slot_function(), _args);
             ^
/usr/include/boost/signals2/detail/variadic_slot_invoker.hpp:106:18: note: in instantiation of function template specialization 'boost::signals2::detail::variadic_slot_invoker<int,
      >::m_invoke<boost::shared_ptr<boost::signals2::detail::connection_body<std::pair<boost::signals2::detail::slot_meta_group, boost::optional<int> >, boost::signals2::slot<int (), boost::function<int ()> >,
      boost::signals2::mutex> > >' requested here
      return m_invoke(connectionBody,
             ^
/usr/include/boost/signals2/detail/slot_call_iterator.hpp:82:35: note: in instantiation of function template specialization 'boost::signals2::detail::variadic_slot_invoker<int,
      >::operator()<boost::shared_ptr<boost::signals2::detail::connection_body<std::pair<boost::signals2::detail::slot_meta_group, boost::optional<int> >, boost::signals2::slot<int (), boost::function<int ()> >,
      boost::signals2::mutex> > >' requested here
          cache->result.reset(cache->f(*iter));
                              ^
/usr/include/boost/iterator/iterator_facade.hpp:514:20: note: in instantiation of member function 'boost::signals2::detail::slot_call_iterator_t<boost::signals2::detail::variadic_slot_invoker<int, >,
      std::_List_iterator<boost::shared_ptr<boost::signals2::detail::connection_body<std::pair<boost::signals2::detail::slot_meta_group, boost::optional<int> >, boost::signals2::slot<int (), boost::function<int
      ()> >, boost::signals2::mutex> > >, boost::signals2::detail::connection_body<std::pair<boost::signals2::detail::slot_meta_group, boost::optional<int> >, boost::signals2::slot<int (), boost::function<int ()>
      >, boost::signals2::mutex> >::dereference' requested here
      return f.dereference();
               ^
/usr/include/boost/iterator/iterator_facade.hpp:639:18: note: (skipping 1 context in backtrace; use -ftemplate-backtrace-limit=0 to see all)
      return iterator_core_access::dereference(this->derived());
             ^
foo.cpp:14:16: note: in instantiation of member function 'boost::iterator_facade<boost::signals2::detail::slot_call_iterator_t<boost::signals2::detail::variadic_slot_invoker<int, >,
      std::_List_iterator<boost::shared_ptr<boost::signals2::detail::connection_body<std::pair<boost::signals2::detail::slot_meta_group, boost::optional<int> >, boost::signals2::slot<int (), boost::function<int
      ()> >, boost::signals2::mutex> > >, boost::signals2::detail::connection_body<std::pair<boost::signals2::detail::slot_meta_group, boost::optional<int> >, boost::signals2::slot<int (), boost::function<int ()>
      >, boost::signals2::mutex> >, int, boost::single_pass_traversal_tag, const int &, long>::operator*' requested here
        if(*first != 0)
           ^
/usr/include/boost/signals2/detail/result_type_wrapper.hpp:53:18: note: in instantiation of function template specialization
      'first_nonzero::operator()<boost::signals2::detail::slot_call_iterator_t<boost::signals2::detail::variadic_slot_invoker<int, >,
      std::_List_iterator<boost::shared_ptr<boost::signals2::detail::connection_body<std::pair<boost::signals2::detail::slot_meta_group, boost::optional<int> >, boost::signals2::slot<int (), boost::function<int
      ()> >, boost::signals2::mutex> > >, boost::signals2::detail::connection_body<std::pair<boost::signals2::detail::slot_meta_group, boost::optional<int> >, boost::signals2::slot<int (), boost::function<int ()>
      >, boost::signals2::mutex> > >' requested here
      return combiner(first, last);
             ^
/usr/include/boost/signals2/detail/signal_template.hpp:241:18: note: in instantiation of function template specialization 'boost::signals2::detail::combiner_invoker<int>::operator()<first_nonzero,
      boost::signals2::detail::slot_call_iterator_t<boost::signals2::detail::variadic_slot_invoker<int, >,
      std::_List_iterator<boost::shared_ptr<boost::signals2::detail::connection_body<std::pair<boost::signals2::detail::slot_meta_group, boost::optional<int> >, boost::signals2::slot<int (), boost::function<int
      ()> >, boost::signals2::mutex> > >, boost::signals2::detail::connection_body<std::pair<boost::signals2::detail::slot_meta_group, boost::optional<int> >, boost::signals2::slot<int (), boost::function<int ()>
      >, boost::signals2::mutex> > >' requested here
      return detail::combiner_invoker<typename combiner_type::result_type>()
             ^
/usr/include/boost/signals2/detail/signal_template.hpp:695:16: note: in instantiation of member function 'boost::signals2::detail::signal_impl<int (), first_nonzero, int, std::less<int>, boost::function<int ()>,
      boost::function<int (const boost::signals2::connection &)>, boost::signals2::mutex>::operator()' requested here
    return (*_pimpl)(BOOST_SIGNALS2_SIGNATURE_ARG_NAMES(BOOST_SIGNALS2_NUM_ARGS));
           ^
foo.cpp:27:13: note: in instantiation of member function 'boost::signals2::signal<int (), first_nonzero, int, std::less<int>, boost::function<int ()>, boost::function<int (const boost::signals2::connection &)>,
      boost::signals2::mutex>::operator()' requested here
    return s();
        ^
/usr/bin/../lib/gcc/x86_64-linux-gnu/4.8/../../../../include/c++/4.8/utility:141:5: note: candidate template ignored: failed template argument deduction
    get(std::pair<_Tp1, _Tp2>& __in) noexcept
    ^
/usr/bin/../lib/gcc/x86_64-linux-gnu/4.8/../../../../include/c++/4.8/utility:146:5: note: candidate template ignored: failed template argument deduction
    get(std::pair<_Tp1, _Tp2>&& __in) noexcept
    ^
/usr/bin/../lib/gcc/x86_64-linux-gnu/4.8/../../../../include/c++/4.8/utility:151:5: note: candidate template ignored: failed template argument deduction
    get(const std::pair<_Tp1, _Tp2>& __in) noexcept
    ^
/usr/bin/../lib/gcc/x86_64-linux-gnu/4.8/../../../../include/c++/4.8/array:267:5: note: candidate template ignored: failed template argument deduction
    get(array<_Tp, _Nm>& __arr) noexcept
    ^
/usr/bin/../lib/gcc/x86_64-linux-gnu/4.8/../../../../include/c++/4.8/array:276:5: note: candidate template ignored: failed template argument deduction
    get(array<_Tp, _Nm>&& __arr) noexcept
    ^
/usr/bin/../lib/gcc/x86_64-linux-gnu/4.8/../../../../include/c++/4.8/array:284:5: note: candidate template ignored: failed template argument deduction
    get(const array<_Tp, _Nm>& __arr) noexcept
    ^
/usr/bin/../lib/gcc/x86_64-linux-gnu/4.8/../../../../include/c++/4.8/tuple:756:5: note: candidate template ignored: failed template argument deduction
    get(tuple<_Elements...>& __t) noexcept
    ^
/usr/bin/../lib/gcc/x86_64-linux-gnu/4.8/../../../../include/c++/4.8/tuple:763:5: note: candidate template ignored: failed template argument deduction
    get(const tuple<_Elements...>& __t) noexcept
    ^
/usr/bin/../lib/gcc/x86_64-linux-gnu/4.8/../../../../include/c++/4.8/tuple:770:5: note: candidate template ignored: failed template argument deduction
    get(tuple<_Elements...>&& __t) noexcept
    ^
1 error generated.

しばらくして、別のコンパイラを試すというクレイジーな考えに屈することにしました。同じスニペットを

g++ -o foo.o -c foo.cpp -std=c++11 -Wall -Wextra -pedantic

エラーはありません。私は実行Debian clang version 3.2-7ubuntu1 (tags/RELEASE_32/final) (based on LLVM 3.2)していg++ (Ubuntu/Linaro 4.8.1-10ubuntu9) 4.8.1ます。ブーストライブラリ 1.54。

プロジェクトの制限により、別のコンパイラを使用することはできません。クランに固執し、引き続きboost::signals2ライブラリを使用する方法はありますか?

score 0 · Accepted Answer

これは古い質問であることは承知していますが、このトピックに関するいくつかのメモは、他の読者に役立つ可能性があります。

問題std::getは a の要素にアクセスするために使用することに関連しているように見えるので、std::tuple最も簡単なことは定義することですBOOST_NO_CXX11_HDR_TUPLE( Boost Macro Reference )。

boost/signals2/detail/variadic_slot_invoker.hppから:

#ifdef BOOST_NO_CXX11_HDR_TUPLE
#include <boost/tuple/tuple.hpp>
#define BOOST_SIGNALS2_TUPLE boost::tuple
#define BOOST_SIGNALS2_GET boost::get
#else
#include <tuple>
#define BOOST_SIGNALS2_TUPLE std::tuple
#define BOOST_SIGNALS2_GET std::get
#endif

このように Boost は / の代わりに / をboost::tuple使用boost::getしstd::tupleますstd::get。(ただしboost::tuple、現時点では可変個引数のテンプレートはサポートされていません)。

もちろん、これは単なる回避策です。Clang (バージョン 3.3 / 3.4 は正常に動作します) をアップグレードするための時間を得ることができます。

c++ - クランはboost::signals2が好きではありませんか?

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