Arbeitet std :: bind im Allgemeinen mit move-only-Typen und insbesondere mit std :: unique_ptr?

Question

Ich versuche, boost :: asio zu verwenden und in ein bisschen ein Sumpf zu laufen.

Ich versuche, den folgenden Code zu kompilieren:

std::unique_ptr<buffer_t> buffer = buffers.pop(); 
std::function<void(const boost::system::error_code&, size_t)> t = std::bind(&tcp_client::handle_read_done, 
                      this, 
                      std::placeholders::_1, 
                      std::placeholders::_2, 
                      std::move(buffer)); 

Alles funktioniert gut, wenn ich die std :: move (Puffer), natürlich sowohl von der Unterschrift der handle_read_done und als übergebene Argument auszuschließen in std :: bind.

Beim Versuch, es in boost :: asio :: async_read_some zu übergeben, beschwert es sich implizit gelöschte Funktionen auf dem Objekt von std :: bind, auf gelöschte Funktionen auf Tupel, die ich wegen der Beweglichkeit, sowie viele boostspezifische Fehler. Wenn ich nur versuche, es in eine std :: -Funktion zu schreiben, die mit der Signatur, die Boost-Aufrufe durchführt, übereinstimmen sollte, bekomme ich dieselben Tupelfehler, also denke ich, dass sie die gleichen sind. Wenn man das Ergebnis von std :: bind automatisch zuweist, ergibt das keinen Compiler-Fehler, aber natürlich kann ich nichts aufrufen.

Was mache ich falsch? Unten ist die Ausgabe von dem Zeitpunkt zugewiesen werden versuchen, std::function<void(const boost::system::error_code&,size_t)>

/usr/lib/gcc/x86_64-unknown-linux-gnu/4.6.2/../../../../include/c++/4.6.2/functional: In static member function ‘static void std::_Function_handler<void(_ArgTypes ...), _Functor>::_M_invoke(const std::_Any_data&, _ArgTypes ...) [with _Functor = std::_Bind<std::_Mem_fn<void (rcon::net::tcp_client::*)(const boost::system::error_code&, long unsigned int, std::unique_ptr<std::array<unsigned char, 10240ul> >)>(rcon::net::tcp_client*, std::_Placeholder<1>, std::_Placeholder<2>, std::unique_ptr<std::array<unsigned char, 10240ul> >)>, _ArgTypes = {const boost::system::error_code&, long unsigned int}]’: 
/usr/lib/gcc/x86_64-unknown-linux-gnu/4.6.2/../../../../include/c++/4.6.2/functional:2148:6: instantiated from ‘std::function<_Res(_ArgTypes ...)>::function(_Functor, typename std::enable_if<(! std::is_integral<_Functor>::value), std::function<_Res(_ArgTypes ...)>::_Useless>::type) [with _Functor = std::_Bind<std::_Mem_fn<void (rcon::net::tcp_client::*)(const boost::system::error_code&, long unsigned int, std::unique_ptr<std::array<unsigned char, 10240ul> >)>(rcon::net::tcp_client*, std::_Placeholder<1>, std::_Placeholder<2>, std::unique_ptr<std::array<unsigned char, 10240ul> >)>, _Res = void, _ArgTypes = {const boost::system::error_code&, long unsigned int}, typename std::enable_if<(! std::is_integral<_Functor>::value), std::function<_Res(_ArgTypes ...)>::_Useless>::type = std::function<void(const boost::system::error_code&, long unsigned int)>::_Useless]’ 
/home/max/dev/rcon/src/net/tcp_client.cpp:98:34: instantiated from here 
/usr/lib/gcc/x86_64-unknown-linux-gnu/4.6.2/../../../../include/c++/4.6.2/functional:1778:2: error: no match for call to ‘(std::_Bind<std::_Mem_fn<void (rcon::net::tcp_client::*)(const boost::system::error_code&, long unsigned int, std::unique_ptr<std::array<unsigned char, 10240ul> >)>(rcon::net::tcp_client*, std::_Placeholder<1>, std::_Placeholder<2>, std::unique_ptr<std::array<unsigned char, 10240ul> >)>) (const boost::system::error_code&, long unsigned int)’ 
/usr/lib/gcc/x86_64-unknown-linux-gnu/4.6.2/../../../../include/c++/4.6.2/functional:1130:11: note: candidates are: 
/usr/lib/gcc/x86_64-unknown-linux-gnu/4.6.2/../../../../include/c++/4.6.2/functional:1201:2: note: template<class ... _Args, class _Result> _Result std::_Bind<_Functor(_Bound_args ...)>::operator()(_Args&& ...) [with _Args = {_Args ...}, _Result = _Result, _Functor = std::_Mem_fn<void (rcon::net::tcp_client::*)(const boost::system::error_code&, long unsigned int, std::unique_ptr<std::array<unsigned char, 10240ul> >)>, _Bound_args = {rcon::net::tcp_client*, std::_Placeholder<1>, std::_Placeholder<2>, std::unique_ptr<std::array<unsigned char, 10240ul> >}] 
/usr/lib/gcc/x86_64-unknown-linux-gnu/4.6.2/../../../../include/c++/4.6.2/functional:1215:2: note: template<class ... _Args, class _Result> _Result std::_Bind<_Functor(_Bound_args ...)>::operator()(_Args&& ...) const [with _Args = {_Args ...}, _Result = _Result, _Functor = std::_Mem_fn<void (rcon::net::tcp_client::*)(const boost::system::error_code&, long unsigned int, std::unique_ptr<std::array<unsigned char, 10240ul> >)>, _Bound_args = {rcon::net::tcp_client*, std::_Placeholder<1>, std::_Placeholder<2>, std::unique_ptr<std::array<unsigned char, 10240ul> >}] 
/usr/lib/gcc/x86_64-unknown-linux-gnu/4.6.2/../../../../include/c++/4.6.2/functional:1229:2: note: template<class ... _Args, class _Result> _Result std::_Bind<_Functor(_Bound_args ...)>::operator()(_Args&& ...) volatile [with _Args = {_Args ...}, _Result = _Result, _Functor = std::_Mem_fn<void (rcon::net::tcp_client::*)(const boost::system::error_code&, long unsigned int, std::unique_ptr<std::array<unsigned char, 10240ul> >)>, _Bound_args = {rcon::net::tcp_client*, std::_Placeholder<1>, std::_Placeholder<2>, std::unique_ptr<std::array<unsigned char, 10240ul> >}] 
/usr/lib/gcc/x86_64-unknown-linux-gnu/4.6.2/../../../../include/c++/4.6.2/functional:1243:2: note: template<class ... _Args, class _Result> _Result std::_Bind<_Functor(_Bound_args ...)>::operator()(_Args&& ...) const volatile [with _Args = {_Args ...}, _Result = _Result, _Functor = std::_Mem_fn<void (rcon::net::tcp_client::*)(const boost::system::error_code&, long unsigned int, std::unique_ptr<std::array<unsigned char, 10240ul> >)>, _Bound_args = {rcon::net::tcp_client*, std::_Placeholder<1>, std::_Placeholder<2>, std::unique_ptr<std::array<unsigned char, 10240ul> >}] 
/usr/lib/gcc/x86_64-unknown-linux-gnu/4.6.2/../../../../include/c++/4.6.2/functional: In static member function ‘static void std::_Function_base::_Base_manager<_Functor>::_M_clone(std::_Any_data&, const std::_Any_data&, std::false_type) [with _Functor = std::_Bind<std::_Mem_fn<void (rcon::net::tcp_client::*)(const boost::system::error_code&, long unsigned int, std::unique_ptr<std::array<unsigned char, 10240ul> >)>(rcon::net::tcp_client*, std::_Placeholder<1>, std::_Placeholder<2>, std::unique_ptr<std::array<unsigned char, 10240ul> >)>, std::false_type = std::integral_constant<bool, false>]’: 
/usr/lib/gcc/x86_64-unknown-linux-gnu/4.6.2/../../../../include/c++/4.6.2/functional:1652:8: instantiated from ‘static bool std::_Function_base::_Base_manager<_Functor>::_M_manager(std::_Any_data&, const std::_Any_data&, std::_Manager_operation) [with _Functor = std::_Bind<std::_Mem_fn<void (rcon::net::tcp_client::*)(const boost::system::error_code&, long unsigned int, std::unique_ptr<std::array<unsigned char, 10240ul> >)>(rcon::net::tcp_client*, std::_Placeholder<1>, std::_Placeholder<2>, std::unique_ptr<std::array<unsigned char, 10240ul> >)>]’ 
/usr/lib/gcc/x86_64-unknown-linux-gnu/4.6.2/../../../../include/c++/4.6.2/functional:2149:6: instantiated from ‘std::function<_Res(_ArgTypes ...)>::function(_Functor, typename std::enable_if<(! std::is_integral<_Functor>::value), std::function<_Res(_ArgTypes ...)>::_Useless>::type) [with _Functor = std::_Bind<std::_Mem_fn<void (rcon::net::tcp_client::*)(const boost::system::error_code&, long unsigned int, std::unique_ptr<std::array<unsigned char, 10240ul> >)>(rcon::net::tcp_client*, std::_Placeholder<1>, std::_Placeholder<2>, std::unique_ptr<std::array<unsigned char, 10240ul> >)>, _Res = void, _ArgTypes = {const boost::system::error_code&, long unsigned int}, typename std::enable_if<(! std::is_integral<_Functor>::value), std::function<_Res(_ArgTypes ...)>::_Useless>::type = std::function<void(const boost::system::error_code&, long unsigned int)>::_Useless]’ 
/home/max/dev/rcon/src/net/tcp_client.cpp:98:34: instantiated from here 
/usr/lib/gcc/x86_64-unknown-linux-gnu/4.6.2/../../../../include/c++/4.6.2/functional:1616:4: error: use of deleted function ‘std::_Bind<_Functor(_Bound_args ...)>::_Bind(const std::_Bind<_Functor(_Bound_args ...)>&) [with _Functor = std::_Mem_fn<void (rcon::net::tcp_client::*)(const boost::system::error_code&, long unsigned int, std::unique_ptr<std::array<unsigned char, 10240ul> >)>, _Bound_args = {rcon::net::tcp_client*, std::_Placeholder<1>, std::_Placeholder<2>, std::unique_ptr<std::array<unsigned char, 10240ul> >}, std::_Bind<_Functor(_Bound_args ...)> = std::_Bind<std::_Mem_fn<void (rcon::net::tcp_client::*)(const boost::system::error_code&, long unsigned int, std::unique_ptr<std::array<unsigned char, 10240ul> >)>(rcon::net::tcp_client*, std::_Placeholder<1>, std::_Placeholder<2>, std::unique_ptr<std::array<unsigned char, 10240ul> >)>]’ 
/usr/lib/gcc/x86_64-unknown-linux-gnu/4.6.2/../../../../include/c++/4.6.2/functional:1189:7: error: ‘std::_Bind<_Functor(_Bound_args ...)>::_Bind(const std::_Bind<_Functor(_Bound_args ...)>&) [with _Functor = std::_Mem_fn<void (rcon::net::tcp_client::*)(const boost::system::error_code&, long unsigned int, std::unique_ptr<std::array<unsigned char, 10240ul> >)>, _Bound_args = {rcon::net::tcp_client*, std::_Placeholder<1>, std::_Placeholder<2>, std::unique_ptr<std::array<unsigned char, 10240ul> >}, std::_Bind<_Functor(_Bound_args ...)> = std::_Bind<std::_Mem_fn<void (rcon::net::tcp_client::*)(const boost::system::error_code&, long unsigned int, std::unique_ptr<std::array<unsigned char, 10240ul> >)>(rcon::net::tcp_client*, std::_Placeholder<1>, std::_Placeholder<2>, std::unique_ptr<std::array<unsigned char, 10240ul> >)>]’ is implicitly deleted because the default definition would be ill-formed: 
/usr/lib/gcc/x86_64-unknown-linux-gnu/4.6.2/../../../../include/c++/4.6.2/functional:1189:7: error: use of deleted function ‘constexpr std::tuple< <template-parameter-1-1> >::tuple(const std::tuple< <template-parameter-1-1> >&) [with _Elements = {rcon::net::tcp_client*, std::_Placeholder<1>, std::_Placeholder<2>, std::unique_ptr<std::array<unsigned char, 10240ul> >}, std::tuple< <template-parameter-1-1> > = std::tuple<rcon::net::tcp_client*, std::_Placeholder<1>, std::_Placeholder<2>, std::unique_ptr<std::array<unsigned char, 10240ul> > >]’ 
In file included from /usr/lib/gcc/x86_64-unknown-linux-gnu/4.6.2/../../../../include/c++/4.6.2/functional:56:0, 
       from /home/max/dev/rcon/include/net/tcp_client.hpp:4, 
       from /home/max/dev/rcon/src/net/tcp_client.cpp:1: 
/usr/lib/gcc/x86_64-unknown-linux-gnu/4.6.2/../../../../include/c++/4.6.2/tuple:249:17: error: ‘constexpr std::tuple< <template-parameter-1-1> >::tuple(const std::tuple< <template-parameter-1-1> >&) [with _Elements = {rcon::net::tcp_client*, std::_Placeholder<1>, std::_Placeholder<2>, std::unique_ptr<std::array<unsigned char, 10240ul> >}, std::tuple< <template-parameter-1-1> > = std::tuple<rcon::net::tcp_client*, std::_Placeholder<1>, std::_Placeholder<2>, std::unique_ptr<std::array<unsigned char, 10240ul> > >]’ is implicitly deleted because the default definition would be ill-formed: 
/usr/lib/gcc/x86_64-unknown-linux-gnu/4.6.2/../../../../include/c++/4.6.2/tuple:249:17: error: use of deleted function ‘constexpr std::_Tuple_impl<_Idx, _Head, _Tail ...>::_Tuple_impl(const std::_Tuple_impl<_Idx, _Head, _Tail ...>&) [with long unsigned int _Idx = 0ul, _Head = rcon::net::tcp_client*, _Tail = {std::_Placeholder<1>, std::_Placeholder<2>, std::unique_ptr<std::array<unsigned char, 10240ul> >}, std::_Tuple_impl<_Idx, _Head, _Tail ...> = std::_Tuple_impl<0ul, rcon::net::tcp_client*, std::_Placeholder<1>, std::_Placeholder<2>, std::unique_ptr<std::array<unsigned char, 10240ul> > >]’ 
/usr/lib/gcc/x86_64-unknown-linux-gnu/4.6.2/../../../../include/c++/4.6.2/tuple:170:17: error: ‘constexpr std::_Tuple_impl<_Idx, _Head, _Tail ...>::_Tuple_impl(const std::_Tuple_impl<_Idx, _Head, _Tail ...>&) [with long unsigned int _Idx = 0ul, _Head = rcon::net::tcp_client*, _Tail = {std::_Placeholder<1>, std::_Placeholder<2>, std::unique_ptr<std::array<unsigned char, 10240ul> >}, std::_Tuple_impl<_Idx, _Head, _Tail ...> = std::_Tuple_impl<0ul, rcon::net::tcp_client*, std::_Placeholder<1>, std::_Placeholder<2>, std::unique_ptr<std::array<unsigned char, 10240ul> > >]’ is implicitly deleted because the default definition would be ill-formed: 
/usr/lib/gcc/x86_64-unknown-linux-gnu/4.6.2/../../../../include/c++/4.6.2/tuple:170:17: error: use of deleted function ‘constexpr std::_Tuple_impl<_Idx, _Head, _Tail ...>::_Tuple_impl(const std::_Tuple_impl<_Idx, _Head, _Tail ...>&) [with long unsigned int _Idx = 1ul, _Head = std::_Placeholder<1>, _Tail = {std::_Placeholder<2>, std::unique_ptr<std::array<unsigned char, 10240ul> >}, std::_Tuple_impl<_Idx, _Head, _Tail ...> = std::_Tuple_impl<1ul, std::_Placeholder<1>, std::_Placeholder<2>, std::unique_ptr<std::array<unsigned char, 10240ul> > >]’ 
/usr/lib/gcc/x86_64-unknown-linux-gnu/4.6.2/../../../../include/c++/4.6.2/tuple:170:17: error: ‘constexpr std::_Tuple_impl<_Idx, _Head, _Tail ...>::_Tuple_impl(const std::_Tuple_impl<_Idx, _Head, _Tail ...>&) [with long unsigned int _Idx = 1ul, _Head = std::_Placeholder<1>, _Tail = {std::_Placeholder<2>, std::unique_ptr<std::array<unsigned char, 10240ul> >}, std::_Tuple_impl<_Idx, _Head, _Tail ...> = std::_Tuple_impl<1ul, std::_Placeholder<1>, std::_Placeholder<2>, std::unique_ptr<std::array<unsigned char, 10240ul> > >]’ is implicitly deleted because the default definition would be ill-formed: 
/usr/lib/gcc/x86_64-unknown-linux-gnu/4.6.2/../../../../include/c++/4.6.2/tuple:170:17: error: use of deleted function ‘constexpr std::_Tuple_impl<_Idx, _Head, _Tail ...>::_Tuple_impl(const std::_Tuple_impl<_Idx, _Head, _Tail ...>&) [with long unsigned int _Idx = 2ul, _Head = std::_Placeholder<2>, _Tail = {std::unique_ptr<std::array<unsigned char, 10240ul> >}, std::_Tuple_impl<_Idx, _Head, _Tail ...> = std::_Tuple_impl<2ul, std::_Placeholder<2>, std::unique_ptr<std::array<unsigned char, 10240ul> > >]’ 
/usr/lib/gcc/x86_64-unknown-linux-gnu/4.6.2/../../../../include/c++/4.6.2/tuple:170:17: error: ‘constexpr std::_Tuple_impl<_Idx, _Head, _Tail ...>::_Tuple_impl(const std::_Tuple_impl<_Idx, _Head, _Tail ...>&) [with long unsigned int _Idx = 2ul, _Head = std::_Placeholder<2>, _Tail = {std::unique_ptr<std::array<unsigned char, 10240ul> >}, std::_Tuple_impl<_Idx, _Head, _Tail ...> = std::_Tuple_impl<2ul, std::_Placeholder<2>, std::unique_ptr<std::array<unsigned char, 10240ul> > >]’ is implicitly deleted because the default definition would be ill-formed: 
/usr/lib/gcc/x86_64-unknown-linux-gnu/4.6.2/../../../../include/c++/4.6.2/tuple:170:17: error: use of deleted function ‘constexpr std::_Tuple_impl<_Idx, _Head, _Tail ...>::_Tuple_impl(const std::_Tuple_impl<_Idx, _Head, _Tail ...>&) [with long unsigned int _Idx = 3ul, _Head = std::unique_ptr<std::array<unsigned char, 10240ul> >, _Tail = {}, std::_Tuple_impl<_Idx, _Head, _Tail ...> = std::_Tuple_impl<3ul, std::unique_ptr<std::array<unsigned char, 10240ul> > >]’ 
/usr/lib/gcc/x86_64-unknown-linux-gnu/4.6.2/../../../../include/c++/4.6.2/tuple:170:17: error: ‘constexpr std::_Tuple_impl<_Idx, _Head, _Tail ...>::_Tuple_impl(const std::_Tuple_impl<_Idx, _Head, _Tail ...>&) [with long unsigned int _Idx = 3ul, _Head = std::unique_ptr<std::array<unsigned char, 10240ul> >, _Tail = {}, std::_Tuple_impl<_Idx, _Head, _Tail ...> = std::_Tuple_impl<3ul, std::unique_ptr<std::array<unsigned char, 10240ul> > >]’ is implicitly deleted because the default definition would be ill-formed: 
/usr/lib/gcc/x86_64-unknown-linux-gnu/4.6.2/../../../../include/c++/4.6.2/tuple:170:17: error: use of deleted function ‘std::_Head_base<3ul, std::unique_ptr<std::array<unsigned char, 10240ul> >, false>::_Head_base(const std::_Head_base<3ul, std::unique_ptr<std::array<unsigned char, 10240ul> >, false>&)’ 
/usr/lib/gcc/x86_64-unknown-linux-gnu/4.6.2/../../../../include/c++/4.6.2/tuple:91:12: error: ‘std::_Head_base<3ul, std::unique_ptr<std::array<unsigned char, 10240ul> >, false>::_Head_base(const std::_Head_base<3ul, std::unique_ptr<std::array<unsigned char, 10240ul> >, false>&)’ is implicitly deleted because the default definition would be ill-formed: 
/usr/lib/gcc/x86_64-unknown-linux-gnu/4.6.2/../../../../include/c++/4.6.2/tuple:91:12: error: use of deleted function ‘std::unique_ptr<_Tp, _Dp>::unique_ptr(const std::unique_ptr<_Tp, _Dp>&) [with _Tp = std::array<unsigned char, 10240ul>, _Dp = std::default_delete<std::array<unsigned char, 10240ul> >, std::unique_ptr<_Tp, _Dp> = std::unique_ptr<std::array<unsigned char, 10240ul> >]’ 
/usr/lib/gcc/x86_64-unknown-linux-gnu/4.6.2/../../../../include/c++/4.6.2/bits/unique_ptr.h:256:7: error: declared here 

Update:

Ich verstehe, dass die oben nicht zu funktionieren scheint. Aber sollte dann die folgende Arbeit nicht funktionieren?

std::unique_ptr<buffer_t> buffer = buffers.pop(); 

    auto t = std::bind(&tcp_client::handle_read_done, 
      this, 
      std::placeholders::_1, 
      std::placeholders::_2, 
      std::move(buffer)); 
    size_t var = 10; 
    boost::system::error_code code; 
    t(code, var); 

Wo die Unterschrift von handle_read_done ist

void tcp_client::handle_read_done(const boost::system::error_code & error, size_t bytes_read, std::unique_ptr<buffer_t> buffer) 

Es fühlt sich an wie ich etwas sehr offensichtlich fehle.

Fehlermeldung:

/home/max/dev/rcon/src/net/tcp_client.cpp: In member function ‘void rcon::net::tcp_client::handle_connect_done(const boost::system::error_code&, const string&)’: 
/home/max/dev/rcon/src/net/tcp_client.cpp:101:15: error: no match for call to ‘(std::_Bind<std::_Mem_fn<void (rcon::net::tcp_client::*)(const boost::system::error_code&, long unsigned int, std::unique_ptr<std::array<unsigned char, 10240ul> >)>(rcon::net::tcp_client*, std::_Placeholder<1>, std::_Placeholder<2>, std::unique_ptr<std::array<unsigned char, 10240ul> >)>) (boost::system::error_code&, size_t&)’ 
/usr/lib/gcc/x86_64-unknown-linux-gnu/4.6.2/../../../../include/c++/4.6.2/functional:1130:11: note: candidates are: 
/usr/lib/gcc/x86_64-unknown-linux-gnu/4.6.2/../../../../include/c++/4.6.2/functional:1201:2: note: template<class ... _Args, class _Result> _Result std::_Bind<_Functor(_Bound_args ...)>::operator()(_Args&& ...) [with _Args = {_Args ...}, _Result = _Result, _Functor = std::_Mem_fn<void (rcon::net::tcp_client::*)(const boost::system::error_code&, long unsigned int, std::unique_ptr<std::array<unsigned char, 10240ul> >)>, _Bound_args = {rcon::net::tcp_client*, std::_Placeholder<1>, std::_Placeholder<2>, std::unique_ptr<std::array<unsigned char, 10240ul> >}] 
/usr/lib/gcc/x86_64-unknown-linux-gnu/4.6.2/../../../../include/c++/4.6.2/functional:1215:2: note: template<class ... _Args, class _Result> _Result std::_Bind<_Functor(_Bound_args ...)>::operator()(_Args&& ...) const [with _Args = {_Args ...}, _Result = _Result, _Functor = std::_Mem_fn<void (rcon::net::tcp_client::*)(const boost::system::error_code&, long unsigned int, std::unique_ptr<std::array<unsigned char, 10240ul> >)>, _Bound_args = {rcon::net::tcp_client*, std::_Placeholder<1>, std::_Placeholder<2>, std::unique_ptr<std::array<unsigned char, 10240ul> >}] 
/usr/lib/gcc/x86_64-unknown-linux-gnu/4.6.2/../../../../include/c++/4.6.2/functional:1229:2: note: template<class ... _Args, class _Result> _Result std::_Bind<_Functor(_Bound_args ...)>::operator()(_Args&& ...) volatile [with _Args = {_Args ...}, _Result = _Result, _Functor = std::_Mem_fn<void (rcon::net::tcp_client::*)(const boost::system::error_code&, long unsigned int, std::unique_ptr<std::array<unsigned char, 10240ul> >)>, _Bound_args = {rcon::net::tcp_client*, std::_Placeholder<1>, std::_Placeholder<2>, std::unique_ptr<std::array<unsigned char, 10240ul> >}] 
/usr/lib/gcc/x86_64-unknown-linux-gnu/4.6.2/../../../../include/c++/4.6.2/functional:1243:2: note: template<class ... _Args, class _Result> _Result std::_Bind<_Functor(_Bound_args ...)>::operator()(_Args&& ...) const volatile [with _Args = {_Args ...}, _Result = _Result, _Functor = std::_Mem_fn<void (rcon::net::tcp_client::*)(const boost::system::error_code&, long unsigned int, std::unique_ptr<std::array<unsigned char, 10240ul> >)>, _Bound_args = {rcon::net::tcp_client*, std::_Placeholder<1>, std::_Placeholder<2>, std::unique_ptr<std::array<unsigned char, 10240ul> >}] 

Answer 1

std::bind funktioniert gut mit Move-nur-Typen. Es wird jedoch nur ein Move-Funktor erstellt. std::function erfordert einen kopierfähigen Funktor. Es klingt wie boost::asio tut auch.

Wenn Sie den Move-only-Funktor bind aufrufen, übergibt er seine gebundenen Argumente als lvalues ​​an den Zieloperator(). Wenn also eines Ihrer gebundenen Argumente move-only ist, muss der Zieloperator() dieses Argument nach (möglicherweise const) lvalue reference nehmen.