无法创建MoveConstructibles的地图(Can't create map of MoveConstructibles)
我有一个包含std::unique_ptr<> ，我想把这个类的实例放在std::map<> 。 我认为推动将移动语义引入C ++的其中一个原因是将unique_ptrs东西放在标准容器中（这在矢量的情况下确实有效）。 但在我看来， std::map<>不喜欢这个想法。 为什么会这样？
#include <map> #include <memory> int main() { std::map<int,std::unique_ptr<int>> map; // error on the line that follows (use of disabled lvalue copy constructor) map.insert(std::make_pair(1,std::unique_ptr<int>(new int(2)))); return 0; }谢谢。
- 编辑
为了更清楚，确切的错误消息是：
mingw32-g++.exe --std=gnu++0x -ID:\CodeEnv\Libraries\Boost -c D:\CodeEnv\CodeMess\Untitled1.cpp -o D:\CodeEnv\CodeMess\Untitled1.o mingw32-g++.exe -o D:\CodeEnv\CodeMess\Untitled1.exe D:\CodeEnv\CodeMess\Untitled1.o In file included from c:\mingw\bin\../lib/gcc/mingw32/4.4.1/include/c++/bits/stl_algobase.h:66, from c:\mingw\bin\../lib/gcc/mingw32/4.4.1/include/c++/bits/stl_tree.h:62, from c:\mingw\bin\../lib/gcc/mingw32/4.4.1/include/c++/map:60, from D:\CodeEnv\CodeMess\Untitled1.cpp:1: c:\mingw\bin\../lib/gcc/mingw32/4.4.1/include/c++/bits/unique_ptr.h: In copy constructor 'std::pair<const int, std::unique_ptr<int, std::default_delete<int> > >::pair(const std::pair<const int, std::unique_ptr<int, std::default_delete<int> > >&)': c:\mingw\bin\../lib/gcc/mingw32/4.4.1/include/c++/bits/stl_pair.h:68: instantiated from 'std::_Rb_tree_node<_Val>::_Rb_tree_node(_Args&& ...) [with _Args = const std::pair<const int, std::unique_ptr<int, std::default_delete<int> > >&, _Val = std::pair<const int, std::unique_ptr<int, std::default_delete<int> > >]' c:\mingw\bin\../lib/gcc/mingw32/4.4.1/include/c++/ext/new_allocator.h:111: instantiated from 'void __gnu_cxx::new_allocator<_Tp>::construct(_Tp*, _Args&& ...) [with _Args = const std::pair<const int, std::unique_ptr<int, std::default_delete<int> > >&, _Tp = std::_Rb_tree_node<std::pair<const int, std::unique_ptr<int, std::default_delete<int> > > >]' c:\mingw\bin\../lib/gcc/mingw32/4.4.1/include/c++/bits/stl_tree.h:394: instantiated from 'std::_Rb_tree_node<_Val>* std::_Rb_tree<_Key, _Val, _KeyOfValue, _Compare, _Alloc>::_M_create_node(_Args&& ...) [with _Args = const std::pair<const int, std::unique_ptr<int, std::default_delete<int> > >&, _Key = int, _Val = std::pair<const int, std::unique_ptr<int, std::default_delete<int> > >, _KeyOfValue = std::_Select1st<std::pair<const int, std::unique_ptr<int, std::default_delete<int> > > >, _Compare = std::less<int>, _Alloc = std::allocator<std::pair<const int, std::unique_ptr<int, std::default_delete<int> > > >]' c:\mingw\bin\../lib/gcc/mingw32/4.4.1/include/c++/bits/stl_tree.h:881: instantiated from 'std::_Rb_tree_iterator<_Val> std::_Rb_tree<_Key, _Val, _KeyOfValue, _Compare, _Alloc>::_M_insert_(const std::_Rb_tree_node_base*, const std::_Rb_tree_node_base*, const _Val&) [with _Key = int, _Val = std::pair<const int, std::unique_ptr<int, std::default_delete<int> > >, _KeyOfValue = std::_Select1st<std::pair<const int, std::unique_ptr<int, std::default_delete<int> > > >, _Compare = std::less<int>, _Alloc = std::allocator<std::pair<const int, std::unique_ptr<int, std::default_delete<int> > > >]' c:\mingw\bin\../lib/gcc/mingw32/4.4.1/include/c++/bits/stl_tree.h:1177: instantiated from 'std::pair<typename std::_Rb_tree<_Key, _Val, _KeyOfValue, _Compare, _Alloc>::iterator, bool> std::_Rb_tree<_Key, _Val, _KeyOfValue, _Compare, _Alloc>::_M_insert_unique(const _Val&) [with _Key = int, _Val = std::pair<const int, std::unique_ptr<int, std::default_delete<int> > >, _KeyOfValue = std::_Select1st<std::pair<const int, std::unique_ptr<int, std::default_delete<int> > > >, _Compare = std::less<int>, _Alloc = std::allocator<std::pair<const int, std::unique_ptr<int, std::default_delete<int> > > >]' c:\mingw\bin\../lib/gcc/mingw32/4.4.1/include/c++/bits/stl_map.h:500: instantiated from 'std::pair<typename std::_Rb_tree<_Key, std::pair<const _Key, _Tp>, std::_Select1st<std::pair<const _Key, _Tp> >, _Compare, typename _Alloc::rebind<std::pair<const _Key, _Tp> >::other>::iterator, bool> std::map<_Key, _Tp, _Compare, _Alloc>::insert(const std::pair<const _Key, _Tp>&) [with _Key = int, _Tp = std::unique_ptr<int, std::default_delete<int> >, _Compare = std::less<int>, _Alloc = std::allocator<std::pair<const int, std::unique_ptr<int, std::default_delete<int> > > >]' D:\CodeEnv\CodeMess\Untitled1.cpp:7: instantiated from here c:\mingw\bin\../lib/gcc/mingw32/4.4.1/include/c++/bits/unique_ptr.h:214: error: deleted function 'std::unique_ptr<_Tp, _Tp_Deleter>::unique_ptr(const std::unique_ptr<_Tp, _Tp_Deleter>&) [with _Tp = int, _Tp_Deleter = std::default_delete<int>]' c:\mingw\bin\../lib/gcc/mingw32/4.4.1/include/c++/bits/stl_pair.h:68: error: used here In file included from c:\mingw\bin\../lib/gcc/mingw32/4.4.1/include/c++/map:60, from D:\CodeEnv\CodeMess\Untitled1.cpp:1: c:\mingw\bin\../lib/gcc/mingw32/4.4.1/include/c++/bits/stl_tree.h: In constructor 'std::_Rb_tree_node<_Val>::_Rb_tree_node(_Args&& ...) [with _Args = const std::pair<const int, std::unique_ptr<int, std::default_delete<int> > >&, _Val = std::pair<const int, std::unique_ptr<int, std::default_delete<int> > >]': c:\mingw\bin\../lib/gcc/mingw32/4.4.1/include/c++/bits/stl_tree.h:136: note: synthesized method 'std::pair<const int, std::unique_ptr<int, std::default_delete<int> > >::pair(const std::pair<const int, std::unique_ptr<int, std::default_delete<int> > >&)' first required here它看起来像是std::pair<>的一个问题，但单独使用时效果非常好：
int main() { std::pair<int,std::unique_ptr<int>> pair; pair = std::make_pair(1,std::unique_ptr<int>(new int(2))); // no errors return 0; }虽然这显然并不意味着它不能被滥用：
int main() { std::pair<int,std::unique_ptr<int>> pair1,pair2; pair1 = std::make_pair(1,std::unique_ptr<int>(new int(2))); // no errors pair2 = pair1; // BOOM ! Copy from lvalue return 0; }这可能是std::map<>发生的事情。
线索？
- 编辑
回顾错误消息，它确实是TDM-GCC 4.4.1的std::map<>实现的问题。 它似乎没有像std::vector<>::push_back(value_type&&)这样的移动语义感知插入方法。
现在做什么？
I have a class containing a std::unique_ptr<> and I want to put instances of this class inside of an std::map<>. I thought one of the things that motivated the introduction of move semantics to C++ was the possibility of putting things like unique_ptrs inside standard containers (and that really works, in the case of vectors). But it seems to me that std::map<> doesn't like this idea. Why is this so?
#include <map> #include <memory> int main() { std::map<int,std::unique_ptr<int>> map; // error on the line that follows (use of disabled lvalue copy constructor) map.insert(std::make_pair(1,std::unique_ptr<int>(new int(2)))); return 0; }Thanks.
-- edit
Just to be more clear, the exact error messages are:
mingw32-g++.exe --std=gnu++0x -ID:\CodeEnv\Libraries\Boost -c D:\CodeEnv\CodeMess\Untitled1.cpp -o D:\CodeEnv\CodeMess\Untitled1.o mingw32-g++.exe -o D:\CodeEnv\CodeMess\Untitled1.exe D:\CodeEnv\CodeMess\Untitled1.o In file included from c:\mingw\bin\../lib/gcc/mingw32/4.4.1/include/c++/bits/stl_algobase.h:66, from c:\mingw\bin\../lib/gcc/mingw32/4.4.1/include/c++/bits/stl_tree.h:62, from c:\mingw\bin\../lib/gcc/mingw32/4.4.1/include/c++/map:60, from D:\CodeEnv\CodeMess\Untitled1.cpp:1: c:\mingw\bin\../lib/gcc/mingw32/4.4.1/include/c++/bits/unique_ptr.h: In copy constructor 'std::pair<const int, std::unique_ptr<int, std::default_delete<int> > >::pair(const std::pair<const int, std::unique_ptr<int, std::default_delete<int> > >&)': c:\mingw\bin\../lib/gcc/mingw32/4.4.1/include/c++/bits/stl_pair.h:68: instantiated from 'std::_Rb_tree_node<_Val>::_Rb_tree_node(_Args&& ...) [with _Args = const std::pair<const int, std::unique_ptr<int, std::default_delete<int> > >&, _Val = std::pair<const int, std::unique_ptr<int, std::default_delete<int> > >]' c:\mingw\bin\../lib/gcc/mingw32/4.4.1/include/c++/ext/new_allocator.h:111: instantiated from 'void __gnu_cxx::new_allocator<_Tp>::construct(_Tp*, _Args&& ...) [with _Args = const std::pair<const int, std::unique_ptr<int, std::default_delete<int> > >&, _Tp = std::_Rb_tree_node<std::pair<const int, std::unique_ptr<int, std::default_delete<int> > > >]' c:\mingw\bin\../lib/gcc/mingw32/4.4.1/include/c++/bits/stl_tree.h:394: instantiated from 'std::_Rb_tree_node<_Val>* std::_Rb_tree<_Key, _Val, _KeyOfValue, _Compare, _Alloc>::_M_create_node(_Args&& ...) [with _Args = const std::pair<const int, std::unique_ptr<int, std::default_delete<int> > >&, _Key = int, _Val = std::pair<const int, std::unique_ptr<int, std::default_delete<int> > >, _KeyOfValue = std::_Select1st<std::pair<const int, std::unique_ptr<int, std::default_delete<int> > > >, _Compare = std::less<int>, _Alloc = std::allocator<std::pair<const int, std::unique_ptr<int, std::default_delete<int> > > >]' c:\mingw\bin\../lib/gcc/mingw32/4.4.1/include/c++/bits/stl_tree.h:881: instantiated from 'std::_Rb_tree_iterator<_Val> std::_Rb_tree<_Key, _Val, _KeyOfValue, _Compare, _Alloc>::_M_insert_(const std::_Rb_tree_node_base*, const std::_Rb_tree_node_base*, const _Val&) [with _Key = int, _Val = std::pair<const int, std::unique_ptr<int, std::default_delete<int> > >, _KeyOfValue = std::_Select1st<std::pair<const int, std::unique_ptr<int, std::default_delete<int> > > >, _Compare = std::less<int>, _Alloc = std::allocator<std::pair<const int, std::unique_ptr<int, std::default_delete<int> > > >]' c:\mingw\bin\../lib/gcc/mingw32/4.4.1/include/c++/bits/stl_tree.h:1177: instantiated from 'std::pair<typename std::_Rb_tree<_Key, _Val, _KeyOfValue, _Compare, _Alloc>::iterator, bool> std::_Rb_tree<_Key, _Val, _KeyOfValue, _Compare, _Alloc>::_M_insert_unique(const _Val&) [with _Key = int, _Val = std::pair<const int, std::unique_ptr<int, std::default_delete<int> > >, _KeyOfValue = std::_Select1st<std::pair<const int, std::unique_ptr<int, std::default_delete<int> > > >, _Compare = std::less<int>, _Alloc = std::allocator<std::pair<const int, std::unique_ptr<int, std::default_delete<int> > > >]' c:\mingw\bin\../lib/gcc/mingw32/4.4.1/include/c++/bits/stl_map.h:500: instantiated from 'std::pair<typename std::_Rb_tree<_Key, std::pair<const _Key, _Tp>, std::_Select1st<std::pair<const _Key, _Tp> >, _Compare, typename _Alloc::rebind<std::pair<const _Key, _Tp> >::other>::iterator, bool> std::map<_Key, _Tp, _Compare, _Alloc>::insert(const std::pair<const _Key, _Tp>&) [with _Key = int, _Tp = std::unique_ptr<int, std::default_delete<int> >, _Compare = std::less<int>, _Alloc = std::allocator<std::pair<const int, std::unique_ptr<int, std::default_delete<int> > > >]' D:\CodeEnv\CodeMess\Untitled1.cpp:7: instantiated from here c:\mingw\bin\../lib/gcc/mingw32/4.4.1/include/c++/bits/unique_ptr.h:214: error: deleted function 'std::unique_ptr<_Tp, _Tp_Deleter>::unique_ptr(const std::unique_ptr<_Tp, _Tp_Deleter>&) [with _Tp = int, _Tp_Deleter = std::default_delete<int>]' c:\mingw\bin\../lib/gcc/mingw32/4.4.1/include/c++/bits/stl_pair.h:68: error: used here In file included from c:\mingw\bin\../lib/gcc/mingw32/4.4.1/include/c++/map:60, from D:\CodeEnv\CodeMess\Untitled1.cpp:1: c:\mingw\bin\../lib/gcc/mingw32/4.4.1/include/c++/bits/stl_tree.h: In constructor 'std::_Rb_tree_node<_Val>::_Rb_tree_node(_Args&& ...) [with _Args = const std::pair<const int, std::unique_ptr<int, std::default_delete<int> > >&, _Val = std::pair<const int, std::unique_ptr<int, std::default_delete<int> > >]': c:\mingw\bin\../lib/gcc/mingw32/4.4.1/include/c++/bits/stl_tree.h:136: note: synthesized method 'std::pair<const int, std::unique_ptr<int, std::default_delete<int> > >::pair(const std::pair<const int, std::unique_ptr<int, std::default_delete<int> > >&)' first required hereIt would look like that's a problem with std::pair<>, but it works perfectly fine when used alone:
int main() { std::pair<int,std::unique_ptr<int>> pair; pair = std::make_pair(1,std::unique_ptr<int>(new int(2))); // no errors return 0; }Although that obviously doesn't mean it can't be misused:
int main() { std::pair<int,std::unique_ptr<int>> pair1,pair2; pair1 = std::make_pair(1,std::unique_ptr<int>(new int(2))); // no errors pair2 = pair1; // BOOM ! Copy from lvalue return 0; }which probably is what happens inside of std::map<>.
Clues?
-- edit
Reviewing the error messages, it really happens to be a problem with TDM-GCC 4.4.1's std::map<> implementation. It doesn't seem to feature a move semantics-aware insertion method like std::vector<>::push_back(value_type&&).
What to do now?
最满意答案
我遇到了同样的问题。 通过修补bits / stl_map.h和bits / stl_tree.h，我可以毫不费力地添加所需的功能。 要使您的特定示例正常工作，您基本上只需要向map类添加insert（value_type &&）方法。 它与insert（const value_type＆）基本相同，但在适当的地方使用std :: move（）。 您还必须添加正确的支持方法，但您可以使用编译错误来告诉您需要什么。
这个问题已经报告给海湾合作委员会小组（ http://gcc.gnu.org/bugzilla/show_bug.cgi?id=44436 ），有人正在研究它，所以希望我们能看到对关联和无序移动构造的支持容器很快。
I ran into the same problem. I was able to add the required functionality without too much effort by patching bits/stl_map.h and bits/stl_tree.h. To get your particular example to work, you basically just have to add an insert(value_type&&) method to the map class. It is essentially the same as insert(const value_type&), but using std::move() where appropriate. You have to add the right support methods as well, but you can use the compile errors to tell you what is needed.
This issue has been reported to the GCC team (http://gcc.gnu.org/bugzilla/show_bug.cgi?id=44436) and someone is working on it, so hopefully we will see support for move constructibles in associative and unordered containers soon.
无法创建MoveConstructibles的地图(Can't create map of MoveConstructibles)我有一个包含std::unique_ptr<> ，我想把这个类的实例放在std::map<> 。 我认为推动将移动语义引入C ++的其中一个原因是将unique_ptrs东西放在标准容器中（这在矢量的情况下确实有效）。 但在我看来， std::map<>不喜欢这个想法。 为什么会这样？
#include <map> #include <memory> int main() { std::map<int,std::unique_ptr<int>> map; // error on the line that follows (use of disabled lvalue copy constructor) map.insert(std::make_pair(1,std::unique_ptr<int>(new int(2)))); return 0; }谢谢。
- 编辑
为了更清楚，确切的错误消息是：
mingw32-g++.exe --std=gnu++0x -ID:\CodeEnv\Libraries\Boost -c D:\CodeEnv\CodeMess\Untitled1.cpp -o D:\CodeEnv\CodeMess\Untitled1.o mingw32-g++.exe -o D:\CodeEnv\CodeMess\Untitled1.exe D:\CodeEnv\CodeMess\Untitled1.o In file included from c:\mingw\bin\../lib/gcc/mingw32/4.4.1/include/c++/bits/stl_algobase.h:66, from c:\mingw\bin\../lib/gcc/mingw32/4.4.1/include/c++/bits/stl_tree.h:62, from c:\mingw\bin\../lib/gcc/mingw32/4.4.1/include/c++/map:60, from D:\CodeEnv\CodeMess\Untitled1.cpp:1: c:\mingw\bin\../lib/gcc/mingw32/4.4.1/include/c++/bits/unique_ptr.h: In copy constructor 'std::pair<const int, std::unique_ptr<int, std::default_delete<int> > >::pair(const std::pair<const int, std::unique_ptr<int, std::default_delete<int> > >&)': c:\mingw\bin\../lib/gcc/mingw32/4.4.1/include/c++/bits/stl_pair.h:68: instantiated from 'std::_Rb_tree_node<_Val>::_Rb_tree_node(_Args&& ...) [with _Args = const std::pair<const int, std::unique_ptr<int, std::default_delete<int> > >&, _Val = std::pair<const int, std::unique_ptr<int, std::default_delete<int> > >]' c:\mingw\bin\../lib/gcc/mingw32/4.4.1/include/c++/ext/new_allocator.h:111: instantiated from 'void __gnu_cxx::new_allocator<_Tp>::construct(_Tp*, _Args&& ...) [with _Args = const std::pair<const int, std::unique_ptr<int, std::default_delete<int> > >&, _Tp = std::_Rb_tree_node<std::pair<const int, std::unique_ptr<int, std::default_delete<int> > > >]' c:\mingw\bin\../lib/gcc/mingw32/4.4.1/include/c++/bits/stl_tree.h:394: instantiated from 'std::_Rb_tree_node<_Val>* std::_Rb_tree<_Key, _Val, _KeyOfValue, _Compare, _Alloc>::_M_create_node(_Args&& ...) [with _Args = const std::pair<const int, std::unique_ptr<int, std::default_delete<int> > >&, _Key = int, _Val = std::pair<const int, std::unique_ptr<int, std::default_delete<int> > >, _KeyOfValue = std::_Select1st<std::pair<const int, std::unique_ptr<int, std::default_delete<int> > > >, _Compare = std::less<int>, _Alloc = std::allocator<std::pair<const int, std::unique_ptr<int, std::default_delete<int> > > >]' c:\mingw\bin\../lib/gcc/mingw32/4.4.1/include/c++/bits/stl_tree.h:881: instantiated from 'std::_Rb_tree_iterator<_Val> std::_Rb_tree<_Key, _Val, _KeyOfValue, _Compare, _Alloc>::_M_insert_(const std::_Rb_tree_node_base*, const std::_Rb_tree_node_base*, const _Val&) [with _Key = int, _Val = std::pair<const int, std::unique_ptr<int, std::default_delete<int> > >, _KeyOfValue = std::_Select1st<std::pair<const int, std::unique_ptr<int, std::default_delete<int> > > >, _Compare = std::less<int>, _Alloc = std::allocator<std::pair<const int, std::unique_ptr<int, std::default_delete<int> > > >]' c:\mingw\bin\../lib/gcc/mingw32/4.4.1/include/c++/bits/stl_tree.h:1177: instantiated from 'std::pair<typename std::_Rb_tree<_Key, _Val, _KeyOfValue, _Compare, _Alloc>::iterator, bool> std::_Rb_tree<_Key, _Val, _KeyOfValue, _Compare, _Alloc>::_M_insert_unique(const _Val&) [with _Key = int, _Val = std::pair<const int, std::unique_ptr<int, std::default_delete<int> > >, _KeyOfValue = std::_Select1st<std::pair<const int, std::unique_ptr<int, std::default_delete<int> > > >, _Compare = std::less<int>, _Alloc = std::allocator<std::pair<const int, std::unique_ptr<int, std::default_delete<int> > > >]' c:\mingw\bin\../lib/gcc/mingw32/4.4.1/include/c++/bits/stl_map.h:500: instantiated from 'std::pair<typename std::_Rb_tree<_Key, std::pair<const _Key, _Tp>, std::_Select1st<std::pair<const _Key, _Tp> >, _Compare, typename _Alloc::rebind<std::pair<const _Key, _Tp> >::other>::iterator, bool> std::map<_Key, _Tp, _Compare, _Alloc>::insert(const std::pair<const _Key, _Tp>&) [with _Key = int, _Tp = std::unique_ptr<int, std::default_delete<int> >, _Compare = std::less<int>, _Alloc = std::allocator<std::pair<const int, std::unique_ptr<int, std::default_delete<int> > > >]' D:\CodeEnv\CodeMess\Untitled1.cpp:7: instantiated from here c:\mingw\bin\../lib/gcc/mingw32/4.4.1/include/c++/bits/unique_ptr.h:214: error: deleted function 'std::unique_ptr<_Tp, _Tp_Deleter>::unique_ptr(const std::unique_ptr<_Tp, _Tp_Deleter>&) [with _Tp = int, _Tp_Deleter = std::default_delete<int>]' c:\mingw\bin\../lib/gcc/mingw32/4.4.1/include/c++/bits/stl_pair.h:68: error: used here In file included from c:\mingw\bin\../lib/gcc/mingw32/4.4.1/include/c++/map:60, from D:\CodeEnv\CodeMess\Untitled1.cpp:1: c:\mingw\bin\../lib/gcc/mingw32/4.4.1/include/c++/bits/stl_tree.h: In constructor 'std::_Rb_tree_node<_Val>::_Rb_tree_node(_Args&& ...) [with _Args = const std::pair<const int, std::unique_ptr<int, std::default_delete<int> > >&, _Val = std::pair<const int, std::unique_ptr<int, std::default_delete<int> > >]': c:\mingw\bin\../lib/gcc/mingw32/4.4.1/include/c++/bits/stl_tree.h:136: note: synthesized method 'std::pair<const int, std::unique_ptr<int, std::default_delete<int> > >::pair(const std::pair<const int, std::unique_ptr<int, std::default_delete<int> > >&)' first required here它看起来像是std::pair<>的一个问题，但单独使用时效果非常好：
int main() { std::pair<int,std::unique_ptr<int>> pair; pair = std::make_pair(1,std::unique_ptr<int>(new int(2))); // no errors return 0; }虽然这显然并不意味着它不能被滥用：
int main() { std::pair<int,std::unique_ptr<int>> pair1,pair2; pair1 = std::make_pair(1,std::unique_ptr<int>(new int(2))); // no errors pair2 = pair1; // BOOM ! Copy from lvalue return 0; }这可能是std::map<>发生的事情。
线索？
- 编辑
回顾错误消息，它确实是TDM-GCC 4.4.1的std::map<>实现的问题。 它似乎没有像std::vector<>::push_back(value_type&&)这样的移动语义感知插入方法。
现在做什么？
I have a class containing a std::unique_ptr<> and I want to put instances of this class inside of an std::map<>. I thought one of the things that motivated the introduction of move semantics to C++ was the possibility of putting things like unique_ptrs inside standard containers (and that really works, in the case of vectors). But it seems to me that std::map<> doesn't like this idea. Why is this so?
#include <map> #include <memory> int main() { std::map<int,std::unique_ptr<int>> map; // error on the line that follows (use of disabled lvalue copy constructor) map.insert(std::make_pair(1,std::unique_ptr<int>(new int(2)))); return 0; }Thanks.
-- edit
Just to be more clear, the exact error messages are:
mingw32-g++.exe --std=gnu++0x -ID:\CodeEnv\Libraries\Boost -c D:\CodeEnv\CodeMess\Untitled1.cpp -o D:\CodeEnv\CodeMess\Untitled1.o mingw32-g++.exe -o D:\CodeEnv\CodeMess\Untitled1.exe D:\CodeEnv\CodeMess\Untitled1.o In file included from c:\mingw\bin\../lib/gcc/mingw32/4.4.1/include/c++/bits/stl_algobase.h:66, from c:\mingw\bin\../lib/gcc/mingw32/4.4.1/include/c++/bits/stl_tree.h:62, from c:\mingw\bin\../lib/gcc/mingw32/4.4.1/include/c++/map:60, from D:\CodeEnv\CodeMess\Untitled1.cpp:1: c:\mingw\bin\../lib/gcc/mingw32/4.4.1/include/c++/bits/unique_ptr.h: In copy constructor 'std::pair<const int, std::unique_ptr<int, std::default_delete<int> > >::pair(const std::pair<const int, std::unique_ptr<int, std::default_delete<int> > >&)': c:\mingw\bin\../lib/gcc/mingw32/4.4.1/include/c++/bits/stl_pair.h:68: instantiated from 'std::_Rb_tree_node<_Val>::_Rb_tree_node(_Args&& ...) [with _Args = const std::pair<const int, std::unique_ptr<int, std::default_delete<int> > >&, _Val = std::pair<const int, std::unique_ptr<int, std::default_delete<int> > >]' c:\mingw\bin\../lib/gcc/mingw32/4.4.1/include/c++/ext/new_allocator.h:111: instantiated from 'void __gnu_cxx::new_allocator<_Tp>::construct(_Tp*, _Args&& ...) [with _Args = const std::pair<const int, std::unique_ptr<int, std::default_delete<int> > >&, _Tp = std::_Rb_tree_node<std::pair<const int, std::unique_ptr<int, std::default_delete<int> > > >]' c:\mingw\bin\../lib/gcc/mingw32/4.4.1/include/c++/bits/stl_tree.h:394: instantiated from 'std::_Rb_tree_node<_Val>* std::_Rb_tree<_Key, _Val, _KeyOfValue, _Compare, _Alloc>::_M_create_node(_Args&& ...) [with _Args = const std::pair<const int, std::unique_ptr<int, std::default_delete<int> > >&, _Key = int, _Val = std::pair<const int, std::unique_ptr<int, std::default_delete<int> > >, _KeyOfValue = std::_Select1st<std::pair<const int, std::unique_ptr<int, std::default_delete<int> > > >, _Compare = std::less<int>, _Alloc = std::allocator<std::pair<const int, std::unique_ptr<int, std::default_delete<int> > > >]' c:\mingw\bin\../lib/gcc/mingw32/4.4.1/include/c++/bits/stl_tree.h:881: instantiated from 'std::_Rb_tree_iterator<_Val> std::_Rb_tree<_Key, _Val, _KeyOfValue, _Compare, _Alloc>::_M_insert_(const std::_Rb_tree_node_base*, const std::_Rb_tree_node_base*, const _Val&) [with _Key = int, _Val = std::pair<const int, std::unique_ptr<int, std::default_delete<int> > >, _KeyOfValue = std::_Select1st<std::pair<const int, std::unique_ptr<int, std::default_delete<int> > > >, _Compare = std::less<int>, _Alloc = std::allocator<std::pair<const int, std::unique_ptr<int, std::default_delete<int> > > >]' c:\mingw\bin\../lib/gcc/mingw32/4.4.1/include/c++/bits/stl_tree.h:1177: instantiated from 'std::pair<typename std::_Rb_tree<_Key, _Val, _KeyOfValue, _Compare, _Alloc>::iterator, bool> std::_Rb_tree<_Key, _Val, _KeyOfValue, _Compare, _Alloc>::_M_insert_unique(const _Val&) [with _Key = int, _Val = std::pair<const int, std::unique_ptr<int, std::default_delete<int> > >, _KeyOfValue = std::_Select1st<std::pair<const int, std::unique_ptr<int, std::default_delete<int> > > >, _Compare = std::less<int>, _Alloc = std::allocator<std::pair<const int, std::unique_ptr<int, std::default_delete<int> > > >]' c:\mingw\bin\../lib/gcc/mingw32/4.4.1/include/c++/bits/stl_map.h:500: instantiated from 'std::pair<typename std::_Rb_tree<_Key, std::pair<const _Key, _Tp>, std::_Select1st<std::pair<const _Key, _Tp> >, _Compare, typename _Alloc::rebind<std::pair<const _Key, _Tp> >::other>::iterator, bool> std::map<_Key, _Tp, _Compare, _Alloc>::insert(const std::pair<const _Key, _Tp>&) [with _Key = int, _Tp = std::unique_ptr<int, std::default_delete<int> >, _Compare = std::less<int>, _Alloc = std::allocator<std::pair<const int, std::unique_ptr<int, std::default_delete<int> > > >]' D:\CodeEnv\CodeMess\Untitled1.cpp:7: instantiated from here c:\mingw\bin\../lib/gcc/mingw32/4.4.1/include/c++/bits/unique_ptr.h:214: error: deleted function 'std::unique_ptr<_Tp, _Tp_Deleter>::unique_ptr(const std::unique_ptr<_Tp, _Tp_Deleter>&) [with _Tp = int, _Tp_Deleter = std::default_delete<int>]' c:\mingw\bin\../lib/gcc/mingw32/4.4.1/include/c++/bits/stl_pair.h:68: error: used here In file included from c:\mingw\bin\../lib/gcc/mingw32/4.4.1/include/c++/map:60, from D:\CodeEnv\CodeMess\Untitled1.cpp:1: c:\mingw\bin\../lib/gcc/mingw32/4.4.1/include/c++/bits/stl_tree.h: In constructor 'std::_Rb_tree_node<_Val>::_Rb_tree_node(_Args&& ...) [with _Args = const std::pair<const int, std::unique_ptr<int, std::default_delete<int> > >&, _Val = std::pair<const int, std::unique_ptr<int, std::default_delete<int> > >]': c:\mingw\bin\../lib/gcc/mingw32/4.4.1/include/c++/bits/stl_tree.h:136: note: synthesized method 'std::pair<const int, std::unique_ptr<int, std::default_delete<int> > >::pair(const std::pair<const int, std::unique_ptr<int, std::default_delete<int> > >&)' first required hereIt would look like that's a problem with std::pair<>, but it works perfectly fine when used alone:
int main() { std::pair<int,std::unique_ptr<int>> pair; pair = std::make_pair(1,std::unique_ptr<int>(new int(2))); // no errors return 0; }Although that obviously doesn't mean it can't be misused:
int main() { std::pair<int,std::unique_ptr<int>> pair1,pair2; pair1 = std::make_pair(1,std::unique_ptr<int>(new int(2))); // no errors pair2 = pair1; // BOOM ! Copy from lvalue return 0; }which probably is what happens inside of std::map<>.
Clues?
-- edit
Reviewing the error messages, it really happens to be a problem with TDM-GCC 4.4.1's std::map<> implementation. It doesn't seem to feature a move semantics-aware insertion method like std::vector<>::push_back(value_type&&).
What to do now?
最满意答案
我遇到了同样的问题。 通过修补bits / stl_map.h和bits / stl_tree.h，我可以毫不费力地添加所需的功能。 要使您的特定示例正常工作，您基本上只需要向map类添加insert（value_type &&）方法。 它与insert（const value_type＆）基本相同，但在适当的地方使用std :: move（）。 您还必须添加正确的支持方法，但您可以使用编译错误来告诉您需要什么。
这个问题已经报告给海湾合作委员会小组（ http://gcc.gnu.org/bugzilla/show_bug.cgi?id=44436 ），有人正在研究它，所以希望我们能看到对关联和无序移动构造的支持容器很快。
I ran into the same problem. I was able to add the required functionality without too much effort by patching bits/stl_map.h and bits/stl_tree.h. To get your particular example to work, you basically just have to add an insert(value_type&&) method to the map class. It is essentially the same as insert(const value_type&), but using std::move() where appropriate. You have to add the right support methods as well, but you can use the compile errors to tell you what is needed.
This issue has been reported to the GCC team (http://gcc.gnu.org/bugzilla/show_bug.cgi?id=44436) and someone is working on it, so hopefully we will see support for move constructibles in associative and unordered containers soon.
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