我尝试将std::condition_variable包含为类成员，并且在将该类的对象传递给std::thread时遇到很多编译错误。我从实际程序中删除了所有其他代码，最后得到了以下最少的代码。删除std::condition_variable不会造成任何问题。我尝试在构造函数中“初始化”变量，并将其设置为inline，但均无济于事。
#include <thread>
#include <condition_variable>
struct ThreadHandler {
void operator()() { }
std::condition_variable cond;
};
int main() {
ThreadHandler th1;
std::thread t1(th1);
t1.join();
}
我在这里做什么错了？
以下是我得到的编译错误：
In file included from main.cpp:1:
/usr/local/include/c++/8.1.0/thread: In instantiation of ‘static std::thread::_Invoker<std::tuple<typename std::decay<_Tp>::type, typename std::decay<_Args>::type ...> > std::thread::__make_invoker(_Callable&&, _Args&& ...) [with _Callable = ThreadHandler&; _Args = {}; typename std::decay<_Tp>::type = ThreadHandler]’:
/usr/local/include/c++/8.1.0/thread:127:22: required from ‘std::thread::thread(_Callable&&, _Args&& ...) [with _Callable = ThreadHandler&; _Args = {}]’
main.cpp:14:23: required from here
/usr/local/include/c++/8.1.0/thread:258:4: error: no matching function for call to ‘std::tuple<ThreadHandler>::tuple(<brace-enclosed initializer list>)’
} };
^
In file included from /usr/local/include/c++/8.1.0/bits/unique_ptr.h:37,
from /usr/local/include/c++/8.1.0/memory:80,
from /usr/local/include/c++/8.1.0/thread:39,
from main.cpp:1:
/usr/local/include/c++/8.1.0/tuple:828:11: note: candidate: ‘template<class _Alloc, class _Dummy, class ... _UElements, typename std::enable_if<((std::_TC<((1 == sizeof... (_UElements)) && (! std::is_same<std::tuple<ThreadHandler>, std::tuple<_Tail ...> >::value)), ThreadHandler>::_MoveConstructibleTuple<_UElements ...>() && (! std::_TC<((1 == sizeof... (_UElements)) && (! std::is_same<std::tuple<ThreadHandler>, std::tuple<_Tail ...> >::value)), ThreadHandler>::_ImplicitlyMoveConvertibleTuple<_UElements ...>())) && std::_TC<(std::is_same<_Dummy, void>::value && (1 == 1)), ThreadHandler>::_NonNestedTuple<tuple<_Tail ...>&&>()), bool>::type <anonymous> > std::tuple<_Elements>::tuple(std::allocator_arg_t, const _Alloc&, std::tuple<_Args2 ...>&&)’
explicit tuple(allocator_arg_t __tag, const _Alloc& __a,
^~~~~
/usr/local/include/c++/8.1.0/tuple:828:11: note: template argument deduction/substitution failed:
In file included from main.cpp:1:
/usr/local/include/c++/8.1.0/thread:258:4: note: candidate expects 3 arguments, 1 provided
} };
^
In file included from /usr/local/include/c++/8.1.0/bits/unique_ptr.h:37,
from /usr/local/include/c++/8.1.0/memory:80,
from /usr/local/include/c++/8.1.0/thread:39,
from main.cpp:1:
/usr/local/include/c++/8.1.0/tuple:813:2: note: candidate: ‘template<class _Alloc, class _Dummy, class ... _UElements, typename std::enable_if<((std::_TC<((1 == sizeof... (_UElements)) && (! std::is_same<std::tuple<ThreadHandler>, std::tuple<_Tail ...> >::value)), ThreadHandler>::_MoveConstructibleTuple<_UElements ...>() && std::_TC<((1 == sizeof... (_UElements)) && (! std::is_same<std::tuple<ThreadHandler>, std::tuple<_Tail ...> >::value)), ThreadHandler>::_ImplicitlyMoveConvertibleTuple<_UElements ...>()) && std::_TC<(std::is_same<_Dummy, void>::value && (1 == 1)), ThreadHandler>::_NonNestedTuple<tuple<_Tail ...>&&>()), bool>::type <anonymous> > std::tuple<_Elements>::tuple(std::allocator_arg_t, const _Alloc&, std::tuple<_Args2 ...>&&)’
tuple(allocator_arg_t __tag, const _Alloc& __a,
^~~~~
/usr/local/include/c++/8.1.0/tuple:813:2: note: template argument deduction/substitution failed:
In file included from main.cpp:1:
/usr/local/include/c++/8.1.0/thread:258:4: note: candidate expects 3 arguments, 1 provided
} };
^
In file included from /usr/local/include/c++/8.1.0/bits/unique_ptr.h:37,
from /usr/local/include/c++/8.1.0/memory:80,
from /usr/local/include/c++/8.1.0/thread:39,
from main.cpp:1:
/usr/local/include/c++/8.1.0/tuple:798:11: note: candidate: ‘template<class _Alloc, class _Dummy, class ... _UElements, typename std::enable_if<((std::_TC<((1 == sizeof... (_UElements)) && (! std::is_same<std::tuple<ThreadHandler>, std::tuple<_Tail ...> >::value)), ThreadHandler>::_ConstructibleTuple<_UElements ...>() && (! std::_TC<((1 == sizeof... (_UElements)) && (! std::is_same<std::tuple<ThreadHandler>, std::tuple<_Tail ...> >::value)), ThreadHandler>::_ImplicitlyConvertibleTuple<_UElements ...>())) && std::_TC<(std::is_same<_Dummy, void>::value && (1 == 1)), ThreadHandler>::_NonNestedTuple<tuple<_Tail ...>&&>()), bool>::type <anonymous> > std::tuple<_Elements>::tuple(std::allocator_arg_t, const _Alloc&, const std::tuple<_Args2 ...>&)’
explicit tuple(allocator_arg_t __tag, const _Alloc& __a,
^~~~~
/usr/local/include/c++/8.1.0/tuple:798:11: note: template argument deduction/substitution failed:
In file included from main.cpp:1:
/usr/local/include/c++/8.1.0/thread:258:4: note: candidate expects 3 arguments, 1 provided
} };
^
In file included from /usr/local/include/c++/8.1.0/bits/unique_ptr.h:37,
from /usr/local/include/c++/8.1.0/memory:80,
from /usr/local/include/c++/8.1.0/thread:39,
from main.cpp:1:
/usr/local/include/c++/8.1.0/tuple:783:2: note: candidate: ‘template<class _Alloc, class _Dummy, class ... _UElements, typename std::enable_if<((std::_TC<((1 == sizeof... (_UElements)) && (! std::is_same<std::tuple<ThreadHandler>, std::tuple<_Tail ...> >::value)), ThreadHandler>::_ConstructibleTuple<_UElements ...>() && std::_TC<((1 == sizeof... (_UElements)) && (! std::is_same<std::tuple<ThreadHandler>, std::tuple<_Tail ...> >::value)), ThreadHandler>::_ImplicitlyConvertibleTuple<_UElements ...>()) && std::_TC<(std::is_same<_Dummy, void>::value && (1 == 1)), ThreadHandler>::_NonNestedTuple<tuple<_Tail ...>&&>()), bool>::type <anonymous> > std::tuple<_Elements>::tuple(std::allocator_arg_t, const _Alloc&, const std::tuple<_Args2 ...>&)’
tuple(allocator_arg_t __tag, const _Alloc& __a,
^~~~~
/usr/local/include/c++/8.1.0/tuple:783:2: note: template argument deduction/substitution failed:
In file included from main.cpp:1:
/usr/local/include/c++/8.1.0/thread:258:4: note: candidate expects 3 arguments, 1 provided
} };
^
In file included from /usr/local/include/c++/8.1.0/bits/unique_ptr.h:37,
from /usr/local/include/c++/8.1.0/memory:80,
from /usr/local/include/c++/8.1.0/thread:39,
from main.cpp:1:
/usr/local/include/c++/8.1.0/tuple:771:2: note: candidate: ‘template<class _Alloc> std::tuple<_Elements>::tuple(std::allocator_arg_t, const _Alloc&, std::tuple<_Elements>&&)’
tuple(allocator_arg_t __tag, const _Alloc& __a, tuple&& __in)
^~~~~
/usr/local/include/c++/8.1.0/tuple:771:2: note: template argument deduction/substitution failed:
In file included from main.cpp:1:
/usr/local/include/c++/8.1.0/thread:258:4: note: candidate expects 3 arguments, 1 provided
} };
^
In file included from /usr/local/include/c++/8.1.0/bits/unique_ptr.h:37,
from /usr/local/include/c++/8.1.0/memory:80,
from /usr/local/include/c++/8.1.0/thread:39,
from main.cpp:1:
/usr/local/include/c++/8.1.0/tuple:767:2: note: candidate: ‘template<class _Alloc> std::tuple<_Elements>::tuple(std::allocator_arg_t, const _Alloc&, const std::tuple<_Elements>&)’
tuple(allocator_arg_t __tag, const _Alloc& __a, const tuple& __in)
^~~~~
/usr/local/include/c++/8.1.0/tuple:767:2: note: template argument deduction/substitution failed:
In file included from main.cpp:1:
/usr/local/include/c++/8.1.0/thread:258:4: note: candidate expects 3 arguments, 1 provided
} };
^
In file included from /usr/local/include/c++/8.1.0/bits/unique_ptr.h:37,
from /usr/local/include/c++/8.1.0/memory:80,
from /usr/local/include/c++/8.1.0/thread:39,
from main.cpp:1:
/usr/local/include/c++/8.1.0/tuple:761:11: note: candidate: ‘template<class _Alloc, class ... _UElements, typename std::enable_if<(std::_TC<((1 == sizeof... (_UElements)) && std::_TC<(sizeof... (_UElements) == 1), ThreadHandler>::_NotSameTuple<_UElements ...>()), ThreadHandler>::_MoveConstructibleTuple<_UElements ...>() && (! std::_TC<((1 == sizeof... (_UElements)) && std::_TC<(sizeof... (_UElements) == 1), ThreadHandler>::_NotSameTuple<_UElements ...>()), ThreadHandler>::_ImplicitlyMoveConvertibleTuple<_UElements ...>())), bool>::type <anonymous> > std::tuple<_Elements>::tuple(std::allocator_arg_t, const _Alloc&, _UElements&& ...)’
explicit tuple(allocator_arg_t __tag, const _Alloc& __a,
^~~~~
/usr/local/include/c++/8.1.0/tuple:761:11: note: template argument deduction/substitution failed:
In file included from main.cpp:1:
/usr/local/include/c++/8.1.0/thread:258:4: note: candidate expects at least 2 arguments, 1 provided
} };
^
In file included from /usr/local/include/c++/8.1.0/bits/unique_ptr.h:37,
from /usr/local/include/c++/8.1.0/memory:80,
from /usr/local/include/c++/8.1.0/thread:39,
from main.cpp:1:
/usr/local/include/c++/8.1.0/tuple:750:2: note: candidate: ‘template<class _Alloc, class ... _UElements, typename std::enable_if<(std::_TC<((1 == sizeof... (_UElements)) && std::_TC<(sizeof... (_UElements) == 1), ThreadHandler>::_NotSameTuple<_UElements ...>()), ThreadHandler>::_MoveConstructibleTuple<_UElements ...>() && std::_TC<((1 == sizeof... (_UElements)) && std::_TC<(sizeof... (_UElements) == 1), ThreadHandler>::_NotSameTuple<_UElements ...>()), ThreadHandler>::_ImplicitlyMoveConvertibleTuple<_UElements ...>()), bool>::type <anonymous> > std::tuple<_Elements>::tuple(std::allocator_arg_t, const _Alloc&, _UElements&& ...)’
tuple(allocator_arg_t __tag, const _Alloc& __a,
^~~~~
/usr/local/include/c++/8.1.0/tuple:750:2: note: template argument deduction/substitution failed:
In file included from main.cpp:1:
/usr/local/include/c++/8.1.0/thread:258:4: note: candidate expects at least 2 arguments, 1 provided
} };
^
In file included from /usr/local/include/c++/8.1.0/bits/unique_ptr.h:37,
from /usr/local/include/c++/8.1.0/memory:80,
from /usr/local/include/c++/8.1.0/thread:39,
from main.cpp:1:
/usr/local/include/c++/8.1.0/tuple:740:11: note: candidate: ‘template<class _Alloc, class _Dummy, typename std::enable_if<(std::_TC<std::is_same<_Dummy, void>::value, ThreadHandler>::_ConstructibleTuple<ThreadHandler>() && (! std::_TC<std::is_same<_Dummy, void>::value, ThreadHandler>::_ImplicitlyConvertibleTuple<ThreadHandler>())), bool>::type <anonymous> > std::tuple<_Elements>::tuple(std::allocator_arg_t, const _Alloc&, const _Elements& ...)’
explicit tuple(allocator_arg_t __tag, const _Alloc& __a,
^~~~~
/usr/local/include/c++/8.1.0/tuple:740:11: note: template argument deduction/substitution failed:
In file included from main.cpp:1:
/usr/local/include/c++/8.1.0/thread:258:4: note: candidate expects 3 arguments, 1 provided
} };
^
In file included from /usr/local/include/c++/8.1.0/bits/unique_ptr.h:37,
from /usr/local/include/c++/8.1.0/memory:80,
from /usr/local/include/c++/8.1.0/thread:39,
from main.cpp:1:
/usr/local/include/c++/8.1.0/tuple:729:2: note: candidate: ‘template<class _Alloc, class _Dummy, typename std::enable_if<(std::_TC<std::is_same<_Dummy, void>::value, ThreadHandler>::_ConstructibleTuple<ThreadHandler>() && std::_TC<std::is_same<_Dummy, void>::value, ThreadHandler>::_ImplicitlyConvertibleTuple<ThreadHandler>()), bool>::type <anonymous> > std::tuple<_Elements>::tuple(std::allocator_arg_t, const _Alloc&, const _Elements& ...)’
tuple(allocator_arg_t __tag, const _Alloc& __a,
^~~~~
/usr/local/include/c++/8.1.0/tuple:729:2: note: template argument deduction/substitution failed:
In file included from main.cpp:1:
/usr/local/include/c++/8.1.0/thread:258:4: note: candidate expects 3 arguments, 1 provided
} };
^
In file included from /usr/local/include/c++/8.1.0/bits/unique_ptr.h:37,
from /usr/local/include/c++/8.1.0/memory:80,
from /usr/local/include/c++/8.1.0/thread:39,
from main.cpp:1:
/usr/local/include/c++/8.1.0/tuple:719:2: note: candidate: ‘template<class _Alloc> std::tuple<_Elements>::tuple(std::allocator_arg_t, const _Alloc&)’
tuple(allocator_arg_t __tag, const _Alloc& __a)
^~~~~
/usr/local/include/c++/8.1.0/tuple:719:2: note: template argument deduction/substitution failed:
In file included from main.cpp:1:
/usr/local/include/c++/8.1.0/thread:258:4: note: candidate expects 2 arguments, 1 provided
} };
^
In file included from /usr/local/include/c++/8.1.0/bits/unique_ptr.h:37,
from /usr/local/include/c++/8.1.0/memory:80,
from /usr/local/include/c++/8.1.0/thread:39,
from main.cpp:1:
/usr/local/include/c++/8.1.0/tuple:713:28: note: candidate: ‘template<class ... _UElements, class _Dummy, typename std::enable_if<((std::_TC<((1 == sizeof... (_UElements)) && (! std::is_same<std::tuple<ThreadHandler>, std::tuple<_Tps ...> >::value)), ThreadHandler>::_MoveConstructibleTuple<_UElements ...>() && (! std::_TC<((1 == sizeof... (_UElements)) && (! std::is_same<std::tuple<ThreadHandler>, std::tuple<_Tps ...> >::value)), ThreadHandler>::_ImplicitlyMoveConvertibleTuple<_UElements ...>())) && std::_TC<(std::is_same<_Dummy, void>::value && (1 == 1)), ThreadHandler>::_NonNestedTuple<tuple<_Tps ...>&&>()), bool>::type <anonymous> > constexpr std::tuple<_Elements>::tuple(std::tuple<_Args1 ...>&&)’
explicit constexpr tuple(tuple<_UElements...>&& __in)
^~~~~
/usr/local/include/c++/8.1.0/tuple:713:28: note: template argument deduction/substitution failed:
In file included from main.cpp:1:
/usr/local/include/c++/8.1.0/thread:258:4: note: ‘ThreadHandler’ is not derived from ‘std::tuple<_Tps ...>’
} };
^
In file included from /usr/local/include/c++/8.1.0/bits/unique_ptr.h:37,
from /usr/local/include/c++/8.1.0/memory:80,
from /usr/local/include/c++/8.1.0/thread:39,
from main.cpp:1:
/usr/local/include/c++/8.1.0/tuple:702:19: note: candidate: ‘template<class ... _UElements, class _Dummy, typename std::enable_if<((std::_TC<((1 == sizeof... (_UElements)) && (! std::is_same<std::tuple<ThreadHandler>, std::tuple<_Tps ...> >::value)), ThreadHandler>::_MoveConstructibleTuple<_UElements ...>() && std::_TC<((1 == sizeof... (_UElements)) && (! std::is_same<std::tuple<ThreadHandler>, std::tuple<_Tps ...> >::value)), ThreadHandler>::_ImplicitlyMoveConvertibleTuple<_UElements ...>()) && std::_TC<(std::is_same<_Dummy, void>::value && (1 == 1)), ThreadHandler>::_NonNestedTuple<tuple<_Tps ...>&&>()), bool>::type <anonymous> > constexpr std::tuple<_Elements>::tuple(std::tuple<_Args1 ...>&&)’
constexpr tuple(tuple<_UElements...>&& __in)
^~~~~
/usr/local/include/c++/8.1.0/tuple:702:19: note: template argument deduction/substitution failed:
In file included from main.cpp:1:
/usr/local/include/c++/8.1.0/thread:258:4: note: ‘ThreadHandler’ is not derived from ‘std::tuple<_Tps ...>’
} };
^
In file included from /usr/local/include/c++/8.1.0/bits/unique_ptr.h:37,
from /usr/local/include/c++/8.1.0/memory:80,
from /usr/local/include/c++/8.1.0/thread:39,
from main.cpp:1:
/usr/local/include/c++/8.1.0/tuple:690:28: note: candidate: ‘template<class ... _UElements, class _Dummy, typename std::enable_if<((std::_TC<((1 == sizeof... (_UElements)) && (! std::is_same<std::tuple<ThreadHandler>, std::tuple<_Tps ...> >::value)), ThreadHandler>::_ConstructibleTuple<_UElements ...>() && (! std::_TC<((1 == sizeof... (_UElements)) && (! std::is_same<std::tuple<ThreadHandler>, std::tuple<_Tps ...> >::value)), ThreadHandler>::_ImplicitlyConvertibleTuple<_UElements ...>())) && std::_TC<(std::is_same<_Dummy, void>::value && (1 == 1)), ThreadHandler>::_NonNestedTuple<const tuple<_Tps ...>&>()), bool>::type <anonymous> > constexpr std::tuple<_Elements>::tuple(const std::tuple<_Args1 ...>&)’
explicit constexpr tuple(const tuple<_UElements...>& __in)
^~~~~
/usr/local/include/c++/8.1.0/tuple:690:28: note: template argument deduction/substitution failed:
In file included from main.cpp:1:
/usr/local/include/c++/8.1.0/thread:258:4: note: ‘ThreadHandler’ is not derived from ‘const std::tuple<_Tps ...>’
} };
^
In file included from /usr/local/include/c++/8.1.0/bits/unique_ptr.h:37,
from /usr/local/include/c++/8.1.0/memory:80,
from /usr/local/include/c++/8.1.0/thread:39,
from main.cpp:1:
/usr/local/include/c++/8.1.0/tuple:678:19: note: candidate: ‘template<class ... _UElements, class _Dummy, typename std::enable_if<((std::_TC<((1 == sizeof... (_UElements)) && (! std::is_same<std::tuple<ThreadHandler>, std::tuple<_Tps ...> >::value)), ThreadHandler>::_ConstructibleTuple<_UElements ...>() && std::_TC<((1 == sizeof... (_UElements)) && (! std::is_same<std::tuple<ThreadHandler>, std::tuple<_Tps ...> >::value)), ThreadHandler>::_ImplicitlyConvertibleTuple<_UElements ...>()) && std::_TC<(std::is_same<_Dummy, void>::value && (1 == 1)), ThreadHandler>::_NonNestedTuple<const tuple<_Tps ...>&>()), bool>::type <anonymous> > constexpr std::tuple<_Elements>::tuple(const std::tuple<_Args1 ...>&)’
constexpr tuple(const tuple<_UElements...>& __in)
^~~~~
/usr/local/include/c++/8.1.0/tuple:678:19: note: template argument deduction/substitution failed:
In file included from main.cpp:1:
/usr/local/include/c++/8.1.0/thread:258:4: note: ‘ThreadHandler’ is not derived from ‘const std::tuple<_Tps ...>’
} };
^
In file included from /usr/local/include/c++/8.1.0/bits/unique_ptr.h:37,
from /usr/local/include/c++/8.1.0/memory:80,
from /usr/local/include/c++/8.1.0/thread:39,
from main.cpp:1:
/usr/local/include/c++/8.1.0/tuple:662:17: note: candidate: ‘constexpr std::tuple<_Elements>::tuple(std::tuple<_Elements>&&) [with _Elements = {ThreadHandler}]’
constexpr tuple(tuple&&) = default;
^~~~~
/usr/local/include/c++/8.1.0/tuple:662:17: note: no known conversion for argument 1 from ‘ThreadHandler’ to ‘std::tuple<ThreadHandler>&&’
/usr/local/include/c++/8.1.0/tuple:657:28: note: candidate: ‘template<class ... _UElements, typename std::enable_if<((std::_TC<((1 == sizeof... (_UElements)) && std::_TC<(sizeof... (_UElements) == 1), ThreadHandler>::_NotSameTuple<_UElements ...>()), ThreadHandler>::_MoveConstructibleTuple<_UElements ...>() && (! std::_TC<((1 == sizeof... (_UElements)) && std::_TC<(sizeof... (_UElements) == 1), ThreadHandler>::_NotSameTuple<_UElements ...>()), ThreadHandler>::_ImplicitlyMoveConvertibleTuple<_UElements ...>())) && (1 >= 1)), bool>::type <anonymous> > constexpr std::tuple<_Elements>::tuple(_UElements&& ...)’
explicit constexpr tuple(_UElements&&... __elements)
^~~~~
/usr/local/include/c++/8.1.0/tuple:657:28: note: template argument deduction/substitution failed:
/usr/local/include/c++/8.1.0/tuple:656:21: error: no type named ‘type’ in ‘struct std::enable_if<false, bool>’
bool>::type=false>
^~~~~
/usr/local/include/c++/8.1.0/tuple:646:19: note: candidate: ‘template<class ... _UElements, typename std::enable_if<((std::_TC<((1 == sizeof... (_UElements)) && std::_TC<(sizeof... (_UElements) == 1), ThreadHandler>::_NotSameTuple<_UElements ...>()), ThreadHandler>::_MoveConstructibleTuple<_UElements ...>() && std::_TC<((1 == sizeof... (_UElements)) && std::_TC<(sizeof... (_UElements) == 1), ThreadHandler>::_NotSameTuple<_UElements ...>()), ThreadHandler>::_ImplicitlyMoveConvertibleTuple<_UElements ...>()) && (1 >= 1)), bool>::type <anonymous> > constexpr std::tuple<_Elements>::tuple(_UElements&& ...)’
constexpr tuple(_UElements&&... __elements)
^~~~~
/usr/local/include/c++/8.1.0/tuple:646:19: note: template argument deduction/substitution failed:
/usr/local/include/c++/8.1.0/tuple:645:21: error: no type named ‘type’ in ‘struct std::enable_if<false, bool>’
bool>::type=true>
^~~~
/usr/local/include/c++/8.1.0/tuple:619:26: note: candidate: ‘template<class _Dummy, typename std::enable_if<((std::_TC<std::is_same<_Dummy, void>::value, ThreadHandler>::_ConstructibleTuple<ThreadHandler>() && (! std::_TC<std::is_same<_Dummy, void>::value, ThreadHandler>::_ImplicitlyConvertibleTuple<ThreadHandler>())) && (1 >= 1)), bool>::type <anonymous> > constexpr std::tuple<_Elements>::tuple(const _Elements& ...)’
explicit constexpr tuple(const _Elements&... __elements)
^~~~~
/usr/local/include/c++/8.1.0/tuple:619:26: note: template argument deduction/substitution failed:
/usr/local/include/c++/8.1.0/tuple:618:28: error: no type named ‘type’ in ‘struct std::enable_if<false, bool>’
bool>::type=false>
^~~~~
/usr/local/include/c++/8.1.0/tuple:608:19: note: candidate: ‘template<class _Dummy, typename std::enable_if<((std::_TC<std::is_same<_Dummy, void>::value, ThreadHandler>::_ConstructibleTuple<ThreadHandler>() && std::_TC<std::is_same<_Dummy, void>::value, ThreadHandler>::_ImplicitlyConvertibleTuple<ThreadHandler>()) && (1 >= 1)), bool>::type <anonymous> > constexpr std::tuple<_Elements>::tuple(const _Elements& ...)’
constexpr tuple(const _Elements&... __elements)
^~~~~
/usr/local/include/c++/8.1.0/tuple:608:19: note: template argument deduction/substitution failed:
/usr/local/include/c++/8.1.0/tuple:607:28: error: no type named ‘type’ in ‘struct std::enable_if<false, bool>’
bool>::type=true>
^~~~
/usr/local/include/c++/8.1.0/tuple:591:26: note: candidate: ‘template<class _Dummy, typename std::enable_if<(std::tuple<ThreadHandler>::_TC2<_Dummy>::_DefaultConstructibleTuple() && (! std::tuple<ThreadHandler>::_TC2<_Dummy>::_ImplicitlyDefaultConstructibleTuple())), bool>::type <anonymous> > constexpr std::tuple<_Elements>::tuple()’
explicit constexpr tuple()
^~~~~
/usr/local/include/c++/8.1.0/tuple:591:26: note: template argument deduction/substitution failed:
In file included from main.cpp:1:
/usr/local/include/c++/8.1.0/thread:258:4: note: candidate expects 0 arguments, 1 provided
} };
^
In file included from /usr/local/include/c++/8.1.0/bits/unique_ptr.h:37,
from /usr/local/include/c++/8.1.0/memory:80,
from /usr/local/include/c++/8.1.0/thread:39,
from main.cpp:1:
/usr/local/include/c++/8.1.0/tuple:581:17: note: candidate: ‘template<class _Dummy, typename std::enable_if<std::tuple<ThreadHandler>::_TC2<_Dummy>::_ImplicitlyDefaultConstructibleTuple(), bool>::type <anonymous> > constexpr std::tuple<_Elements>::tuple()’
constexpr tuple()
^~~~~
/usr/local/include/c++/8.1.0/tuple:581:17: note: template argument deduction/substitution failed:
In file included from main.cpp:1:
/usr/local/include/c++/8.1.0/thread:258:4: note: candidate expects 0 arguments, 1 provided
} };
^
/usr/local/include/c++/8.1.0/thread:258:4: error: could not convert ‘{<expression error>}’ from ‘<brace-enclosed initializer list>’ to ‘std::thread::_Invoker<std::tuple<ThreadHandler> >’
In file included from /usr/local/include/c++/8.1.0/bits/unique_ptr.h:37,
from /usr/local/include/c++/8.1.0/memory:80,
from /usr/local/include/c++/8.1.0/thread:39,
from main.cpp:1:
/usr/local/include/c++/8.1.0/tuple: In instantiation of ‘constexpr std::_Head_base<_Idx, _Head, false>::_Head_base(_UHead&&) [with _UHead = ThreadHandler; long unsigned int _Idx = 0; _Head = ThreadHandler]’:
/usr/local/include/c++/8.1.0/tuple:373:49: required from ‘constexpr std::_Tuple_impl<_Idx, _Head>::_Tuple_impl(std::_Tuple_impl<_Idx, _Head>&&) [with long unsigned int _Idx = 0; _Head = ThreadHandler]’
/usr/local/include/c++/8.1.0/tuple:662:17: required from ‘std::thread::_State_impl<_Callable>::_State_impl(_Callable&&) [with _Callable = std::thread::_Invoker<std::tuple<ThreadHandler> >]’
/usr/local/include/c++/8.1.0/thread:197:20: required from ‘static std::thread::_State_ptr std::thread::_S_make_state(_Callable&&) [with _Callable = std::thread::_Invoker<std::tuple<ThreadHandler> >; std::thread::_State_ptr = std::unique_ptr<std::thread::_State>]’
/usr/local/include/c++/8.1.0/thread:126:38: required from ‘std::thread::thread(_Callable&&, _Args&& ...) [with _Callable = ThreadHandler&; _Args = {}]’
main.cpp:14:23: required from here
/usr/local/include/c++/8.1.0/tuple:133:42: error: use of deleted function ‘ThreadHandler::ThreadHandler(ThreadHandler&&)’
: _M_head_impl(std::forward<_UHead>(__h)) { }
^
main.cpp:4:8: note: ‘ThreadHandler::ThreadHandler(ThreadHandler&&)’ is implicitly deleted because the default definition would be ill-formed:
struct ThreadHandler
^~~~~~~~~~~~~
main.cpp:4:8: error: use of deleted function ‘std::condition_variable::condition_variable(const std::condition_variable&)’
In file included from main.cpp:2:
/usr/local/include/c++/8.1.0/condition_variable:82:5: note: declared here
condition_variable(const condition_variable&) = delete;
^~~~~~~~~~~~~~~~~~
In file included from main.cpp:1:
/usr/local/include/c++/8.1.0/thread: In instantiation of ‘std::thread::_State_impl<_Callable>::_State_impl(_Callable&&) [with _Callable = std::thread::_Invoker<std::tuple<ThreadHandler> >]’:
/usr/local/include/c++/8.1.0/thread:197:20: required from ‘static std::thread::_State_ptr std::thread::_S_make_state(_Callable&&) [with _Callable = std::thread::_Invoker<std::tuple<ThreadHandler> >; std::thread::_State_ptr = std::unique_ptr<std::thread::_State>]’
/usr/local/include/c++/8.1.0/thread:126:38: required from ‘std::thread::thread(_Callable&&, _Args&& ...) [with _Callable = ThreadHandler&; _Args = {}]’
main.cpp:14:23: required from here
/usr/local/include/c++/8.1.0/thread:221:14: note: synthesized method ‘constexpr std::tuple<_Elements>::tuple(std::tuple<_Elements>&&) [with _Elements = {ThreadHandler}]’ first required here
struct _Invoker
^~~~~~~~
/usr/local/include/c++/8.1.0/thread:182:69: note: synthesized method ‘constexpr std::thread::_Invoker<std::tuple<ThreadHandler> >::_Invoker(std::thread::_Invoker<std::tuple<ThreadHandler> >&&)’ first required here
_State_impl(_Callable&& __f) : _M_func(std::forward<_Callable>(__f))
答案 0 :(得分：13)
您将ThreadHandler的实例按值传递给std::thread，但如std::condition_variable的文档所述
类std :: condition_variable是StandardLayoutType。 不是可复制构造，不可移动构造，可复制分配，可移动分配。
重点是我的。因此它也使结构ThreadHandler不可复制/不可移动。可能的解决方案是通过引用将其传递：
std::thread t1(std::ref(th1));
注意：您不必使ThreadHandler成为函子，只需常规方法即可：
struct ThreadHandler {
void thread_func() { }
std::condition_variable cond;
};
int main() {
ThreadHandler th1;
std::thread t1(&ThreadHandler::thread_func, &th1);
t1.join();
}
这不仅可以解决您的问题（我通过了th1的地址，因此没有涉及副本），但使其更具可读性（方法名称是显式的）和灵活的（可以为不同的线程使用不同的方法）
答案 1 :(得分：7)
您永远不能仅复制同步对象。它被锁定了吗？解锁了吗？是在锁定还是解锁？
C ++ condition_variables没有副本构造函数，因此让他们拥有它们是没有意义的。遗憾的是，错误消息没有再有用了。