std::push_heap 和 std::pop_heap 与 MoveConstructible 对象
std::push_heap and std::pop_heap with MoveConstructible objects
我想维护一个有效负载为 MoveConstructible 的堆（因为它们在内部包含 std::unique_ptr。）尽管 documentation suggests that the object must be MoveAssignable and MoveConstructible，这样做会在 GCC 和铿锵
示例代码
我还没有使用 std::unique_ptr，只是禁用了相应的复制操作符):
#include <iostream>
#include <vector>
#include <algorithm>
struct Data {
explicit Data(int value) : value(value) {}
int value;
bool operator<(const Data& d) const {
return value > d.value;
}
/**
* Commenting out the rest of the section for this struct
* gets the code working by using copy operator/ctor.
*/
explicit Data(const Data& d) = delete;
Data& operator=(const Data& d) = delete;
explicit Data(Data&& d) = default;
Data& operator=(Data&& d) = default;
};
struct MinHeap {
void Push(Data&& d) {
container_.emplace_back(std::move(d));
std::push_heap(container_.begin(), container_.end());
}
Data Pop() {
std::pop_heap(container_.begin(), container_.end());
Data d = std::move(container_.back());
container_.pop_back();
return std::move(d);
}
size_t size() const { return container_.size(); }
bool empty() const { return size() == 0; }
private:
std::vector<Data> container_;
};
int main() {
MinHeap h;
h.Push(Data(5));
h.Push(Data(8));
h.Push(Data(11));
h.Push(Data(3));
h.Push(Data(7));
while (!h.empty()) {
Data d = std::move(h.Pop());
std::cout << d.value << std::endl;
}
return 0;
}
知道我做错了什么吗，以及如何让堆使用移动语义？
错误
In file included from /usr/include/c++/4.9.2/bits/stl_pair.h:59:0,
from /usr/include/c++/4.9.2/bits/stl_algobase.h:64,
from /usr/include/c++/4.9.2/bits/char_traits.h:39,
from /usr/include/c++/4.9.2/ios:40,
from /usr/include/c++/4.9.2/ostream:38,
from /usr/include/c++/4.9.2/iostream:39,
from main.cpp:1:
/usr/include/c++/4.9.2/bits/stl_heap.h: In instantiation of 'void std::push_heap(_RAIter, _RAIter) [with _RAIter = __gnu_cxx::__norma
l_iterator<Data*, std::vector<Data> >]':
main.cpp:25:56: required from here
/usr/include/c++/4.9.2/bits/stl_heap.h:164:28: error: no matching function for call to 'Data::Data(std::remove_reference<Data&>::type
)'
_ValueType __value = _GLIBCXX_MOVE(*(__last - 1));
^
In file included from /usr/include/c++/4.9.2/bits/stl_algo.h:61:0,
from /usr/include/c++/4.9.2/algorithm:62,
from main.cpp:3:
/usr/include/c++/4.9.2/bits/stl_heap.h:167:45: error: no matching function for call to 'Data::Data(std::remove_reference<Data&>::type
)'
__gnu_cxx::__ops::__iter_less_val());
^
/usr/include/c++/4.9.2/bits/stl_heap.h:124:5: error: initializing argument 4 of 'void std::__push_heap(_RandomAccessIterator, _Dist
ance, _Distance, _Tp, _Compare) [with _RandomAccessIterator = __gnu_cxx::__normal_iterator<Data*, std::vector<Data> >; _Distance = lo
ng int; _Tp = Data; _Compare = __gnu_cxx::__ops::_Iter_less_val]'
__push_heap(_RandomAccessIterator __first,
^
In file included from /usr/include/c++/4.9.2/bits/stl_pair.h:59:0,
from /usr/include/c++/4.9.2/bits/stl_algobase.h:64,
from /usr/include/c++/4.9.2/bits/char_traits.h:39,
from /usr/include/c++/4.9.2/ios:40,
from /usr/include/c++/4.9.2/ostream:38,
from /usr/include/c++/4.9.2/iostream:39,
from main.cpp:1:
/usr/include/c++/4.9.2/bits/stl_heap.h: In instantiation of 'void std::__pop_heap(_RandomAccessIterator, _RandomAccessIterator, _Rand
omAccessIterator, _Compare) [with _RandomAccessIterator = __gnu_cxx::__normal_iterator<Data*, std::vector<Data> >; _Compare = __gnu_c
xx::__ops::_Iter_less_iter]':
/usr/include/c++/4.9.2/bits/stl_heap.h:280:42: required from 'void std::pop_heap(_RAIter, _RAIter) [with _RAIter = __gnu_cxx::__nor
mal_iterator<Data*, std::vector<Data> >]'
main.cpp:29:55: required from here
/usr/include/c++/4.9.2/bits/stl_heap.h:243:28: error: no matching function for call to 'Data::Data(std::remove_reference<Data&>::type
)'
_ValueType __value = _GLIBCXX_MOVE(*__result);
^
In file included from /usr/include/c++/4.9.2/bits/stl_algo.h:61:0,
from /usr/include/c++/4.9.2/algorithm:62,
from main.cpp:3:
/usr/include/c++/4.9.2/bits/stl_heap.h:247:35: error: no matching function for call to 'Data::Data(std::remove_reference<Data&>::type
)'
_GLIBCXX_MOVE(__value), __comp);
^
/usr/include/c++/4.9.2/bits/stl_heap.h:207:5: error: initializing argument 4 of 'void std::__adjust_heap(_RandomAccessIterator, _Di
stance, _Distance, _Tp, _Compare) [with _RandomAccessIterator = __gnu_cxx::__normal_iterator<Data*, std::vector<Data> >; _Distance =
long int; _Tp = Data; _Compare = __gnu_cxx::__ops::_Iter_less_iter]'
__adjust_heap(_RandomAccessIterator __first, _Distance __holeIndex,
^
切勿将复制构造函数或移动构造函数标记为 explicit。这不违法。它不寻常到令人困惑。没有好处，只有坏处。
移动构造函数中的 explicit 是导致此错误的原因。
我想维护一个有效负载为 MoveConstructible 的堆（因为它们在内部包含 std::unique_ptr。）尽管 documentation suggests that the object must be MoveAssignable and MoveConstructible，这样做会在 GCC 和铿锵
示例代码
我还没有使用 std::unique_ptr，只是禁用了相应的复制操作符):
#include <iostream>
#include <vector>
#include <algorithm>
struct Data {
explicit Data(int value) : value(value) {}
int value;
bool operator<(const Data& d) const {
return value > d.value;
}
/**
* Commenting out the rest of the section for this struct
* gets the code working by using copy operator/ctor.
*/
explicit Data(const Data& d) = delete;
Data& operator=(const Data& d) = delete;
explicit Data(Data&& d) = default;
Data& operator=(Data&& d) = default;
};
struct MinHeap {
void Push(Data&& d) {
container_.emplace_back(std::move(d));
std::push_heap(container_.begin(), container_.end());
}
Data Pop() {
std::pop_heap(container_.begin(), container_.end());
Data d = std::move(container_.back());
container_.pop_back();
return std::move(d);
}
size_t size() const { return container_.size(); }
bool empty() const { return size() == 0; }
private:
std::vector<Data> container_;
};
int main() {
MinHeap h;
h.Push(Data(5));
h.Push(Data(8));
h.Push(Data(11));
h.Push(Data(3));
h.Push(Data(7));
while (!h.empty()) {
Data d = std::move(h.Pop());
std::cout << d.value << std::endl;
}
return 0;
}
知道我做错了什么吗，以及如何让堆使用移动语义？
错误
In file included from /usr/include/c++/4.9.2/bits/stl_pair.h:59:0,
from /usr/include/c++/4.9.2/bits/stl_algobase.h:64,
from /usr/include/c++/4.9.2/bits/char_traits.h:39,
from /usr/include/c++/4.9.2/ios:40,
from /usr/include/c++/4.9.2/ostream:38,
from /usr/include/c++/4.9.2/iostream:39,
from main.cpp:1:
/usr/include/c++/4.9.2/bits/stl_heap.h: In instantiation of 'void std::push_heap(_RAIter, _RAIter) [with _RAIter = __gnu_cxx::__norma
l_iterator<Data*, std::vector<Data> >]':
main.cpp:25:56: required from here
/usr/include/c++/4.9.2/bits/stl_heap.h:164:28: error: no matching function for call to 'Data::Data(std::remove_reference<Data&>::type
)'
_ValueType __value = _GLIBCXX_MOVE(*(__last - 1));
^
In file included from /usr/include/c++/4.9.2/bits/stl_algo.h:61:0,
from /usr/include/c++/4.9.2/algorithm:62,
from main.cpp:3:
/usr/include/c++/4.9.2/bits/stl_heap.h:167:45: error: no matching function for call to 'Data::Data(std::remove_reference<Data&>::type
)'
__gnu_cxx::__ops::__iter_less_val());
^
/usr/include/c++/4.9.2/bits/stl_heap.h:124:5: error: initializing argument 4 of 'void std::__push_heap(_RandomAccessIterator, _Dist
ance, _Distance, _Tp, _Compare) [with _RandomAccessIterator = __gnu_cxx::__normal_iterator<Data*, std::vector<Data> >; _Distance = lo
ng int; _Tp = Data; _Compare = __gnu_cxx::__ops::_Iter_less_val]'
__push_heap(_RandomAccessIterator __first,
^
In file included from /usr/include/c++/4.9.2/bits/stl_pair.h:59:0,
from /usr/include/c++/4.9.2/bits/stl_algobase.h:64,
from /usr/include/c++/4.9.2/bits/char_traits.h:39,
from /usr/include/c++/4.9.2/ios:40,
from /usr/include/c++/4.9.2/ostream:38,
from /usr/include/c++/4.9.2/iostream:39,
from main.cpp:1:
/usr/include/c++/4.9.2/bits/stl_heap.h: In instantiation of 'void std::__pop_heap(_RandomAccessIterator, _RandomAccessIterator, _Rand
omAccessIterator, _Compare) [with _RandomAccessIterator = __gnu_cxx::__normal_iterator<Data*, std::vector<Data> >; _Compare = __gnu_c
xx::__ops::_Iter_less_iter]':
/usr/include/c++/4.9.2/bits/stl_heap.h:280:42: required from 'void std::pop_heap(_RAIter, _RAIter) [with _RAIter = __gnu_cxx::__nor
mal_iterator<Data*, std::vector<Data> >]'
main.cpp:29:55: required from here
/usr/include/c++/4.9.2/bits/stl_heap.h:243:28: error: no matching function for call to 'Data::Data(std::remove_reference<Data&>::type
)'
_ValueType __value = _GLIBCXX_MOVE(*__result);
^
In file included from /usr/include/c++/4.9.2/bits/stl_algo.h:61:0,
from /usr/include/c++/4.9.2/algorithm:62,
from main.cpp:3:
/usr/include/c++/4.9.2/bits/stl_heap.h:247:35: error: no matching function for call to 'Data::Data(std::remove_reference<Data&>::type
)'
_GLIBCXX_MOVE(__value), __comp);
^
/usr/include/c++/4.9.2/bits/stl_heap.h:207:5: error: initializing argument 4 of 'void std::__adjust_heap(_RandomAccessIterator, _Di
stance, _Distance, _Tp, _Compare) [with _RandomAccessIterator = __gnu_cxx::__normal_iterator<Data*, std::vector<Data> >; _Distance =
long int; _Tp = Data; _Compare = __gnu_cxx::__ops::_Iter_less_iter]'
__adjust_heap(_RandomAccessIterator __first, _Distance __holeIndex,
^
切勿将复制构造函数或移动构造函数标记为 explicit。这不违法。它不寻常到令人困惑。没有好处，只有坏处。
移动构造函数中的 explicit 是导致此错误的原因。