5
我有这样的代码：的std ::升压::互斥的地图奇怪的行为
////
// Default Namespaces
///
using namespace std;
typedef map <string, boost::shared_mutex> t_map_shared_mutex;
int main(int argc, char** argv) {
t_map_shared_mutex list_lock;
boost::shared_mutex global_lock;
string i = "ABC";
boost::unique_lock <boost::shared_mutex> l_lock (global_lock);
boost::unique_lock <boost::shared_mutex> lock (list_lock[i]);
//Do Something with that lock
lock.unlock();
l_lock.unlock();
}
这将生成以下错误。从我的理解（我可能在这里很不对头）g ++告诉我，互斥量被作为const值传递......我看不出为什么。
In file included from /usr/include/c++/4.4/utility:63,
from /usr/include/boost/config/no_tr1/utility.hpp:21,
from /usr/include/boost/config/select_stdlib_config.hpp:33,
from /usr/include/boost/config.hpp:40,
from /usr/include/boost/date_time/compiler_config.hpp:12,
from /usr/include/boost/date_time/posix_time/posix_time.hpp:14,
from prova.cpp:5:
/usr/include/c++/4.4/bits/stl_pair.h: In constructor ‘std::pair<_T1, _T2>::pair(const _T1&, const _T2&) [with _T1 = const std::basic_string<char, std::char_traits<char>, std::allocator<char> >, _T2 = boost::shared_mutex]’:
/usr/include/c++/4.4/bits/stl_map.h:450: instantiated from ‘_Tp& std::map<_Key, _Tp, _Compare, _Alloc>::operator[](const _Key&) [with _Key = std::basic_string<char, std::char_traits<char>, std::allocator<char> >, _Tp = boost::shared_mutex, _Compare = std::less<std::basic_string<char, std::char_traits<char>, std::allocator<char> > >, _Alloc = std::allocator<std::pair<const std::basic_string<char, std::char_traits<char>, std::allocator<char> >, boost::shared_mutex> >]’
prova.cpp:66: instantiated from here
/usr/include/c++/4.4/bits/stl_pair.h:84: error: no matching function for call to ‘boost::shared_mutex::shared_mutex(const boost::shared_mutex&)’
/usr/include/boost/thread/pthread/shared_mutex.hpp:47: note: candidates are: boost::shared_mutex::shared_mutex()
/usr/include/boost/thread/pthread/shared_mutex.hpp:21: note: boost::shared_mutex::shared_mutex(boost::shared_mutex&)
/usr/include/c++/4.4/bits/stl_pair.h: In constructor ‘std::pair<_T1, _T2>::pair(const std::pair<_U1, _U2>&) [with _U1 = const std::basic_string<char, std::char_traits<char>, std::allocator<char> >, _U2 = boost::shared_mutex, _T1 = const std::basic_string<char, std::char_traits<char>, std::allocator<char> >, _T2 = boost::shared_mutex]’:
/usr/include/c++/4.4/ext/new_allocator.h:105: instantiated from ‘void __gnu_cxx::new_allocator<_Tp>::construct(_Tp*, const _Tp&) [with _Tp = std::pair<const std::basic_string<char, std::char_traits<char>, std::allocator<char> >, boost::shared_mutex>]’
/usr/include/c++/4.4/bits/stl_tree.h:371: instantiated from ‘std::_Rb_tree_node<_Val>* std::_Rb_tree<_Key, _Val, _KeyOfValue, _Compare, _Alloc>::_M_create_node(const _Val&) [with _Key = std::basic_string<char, std::char_traits<char>, std::allocator<char> >, _Val = std::pair<const std::basic_string<char, std::char_traits<char>, std::allocator<char> >, boost::shared_mutex>, _KeyOfValue = std::_Select1st<std::pair<const std::basic_string<char, std::char_traits<char>, std::allocator<char> >, boost::shared_mutex> >, _Compare = std::less<std::basic_string<char, std::char_traits<char>, std::allocator<char> > >, _Alloc = std::allocator<std::pair<const std::basic_string<char, std::char_traits<char>, std::allocator<char> >, boost::shared_mutex> >]’
/usr/include/c++/4.4/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 = std::basic_string<char, std::char_traits<char>, std::allocator<char> >, _Val = std::pair<const std::basic_string<char, std::char_traits<char>, std::allocator<char> >, boost::shared_mutex>, _KeyOfValue = std::_Select1st<std::pair<const std::basic_string<char, std::char_traits<char>, std::allocator<char> >, boost::shared_mutex> >, _Compare = std::less<std::basic_string<char, std::char_traits<char>, std::allocator<char> > >, _Alloc = std::allocator<std::pair<const std::basic_string<char, std::char_traits<char>, std::allocator<char> >, boost::shared_mutex> >]’
/usr/include/c++/4.4/bits/stl_tree.h:1215: instantiated from ‘std::_Rb_tree_iterator<_Val> std::_Rb_tree<_Key, _Val, _KeyOfValue, _Compare, _Alloc>::_M_insert_unique_(std::_Rb_tree_const_iterator<_Val>, const _Val&) [with _Key = std::basic_string<char, std::char_traits<char>, std::allocator<char> >, _Val = std::pair<const std::basic_string<char, std::char_traits<char>, std::allocator<char> >, boost::shared_mutex>, _KeyOfValue = std::_Select1st<std::pair<const std::basic_string<char, std::char_traits<char>, std::allocator<char> >, boost::shared_mutex> >, _Compare = std::less<std::basic_string<char, std::char_traits<char>, std::allocator<char> > >, _Alloc = std::allocator<std::pair<const std::basic_string<char, std::char_traits<char>, std::allocator<char> >, boost::shared_mutex> >]’
/usr/include/c++/4.4/bits/stl_map.h:540: instantiated from ‘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 std::map<_Key, _Tp, _Compare, _Alloc>::insert(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, const std::pair<const _Key, _Tp>&) [with _Key = std::basic_string<char, std::char_traits<char>, std::allocator<char> >, _Tp = boost::shared_mutex, _Compare = std::less<std::basic_string<char, std::char_traits<char>, std::allocator<char> > >, _Alloc = std::allocator<std::pair<const std::basic_string<char, std::char_traits<char>, std::allocator<char> >, boost::shared_mutex> >]’
/usr/include/c++/4.4/bits/stl_map.h:450: instantiated from ‘_Tp& std::map<_Key, _Tp, _Compare, _Alloc>::operator[](const _Key&) [with _Key = std::basic_string<char, std::char_traits<char>, std::allocator<char> >, _Tp = boost::shared_mutex, _Compare = std::less<std::basic_string<char, std::char_traits<char>, std::allocator<char> > >, _Alloc = std::allocator<std::pair<const std::basic_string<char, std::char_traits<char>, std::allocator<char> >, boost::shared_mutex> >]’
prova.cpp:66: instantiated from here
/usr/include/c++/4.4/bits/stl_pair.h:101: error: no matching function for call to ‘boost::shared_mutex::shared_mutex(const boost::shared_mutex&)’
/usr/include/boost/thread/pthread/shared_mutex.hpp:47: note: candidates are: boost::shared_mutex::shared_mutex()
/usr/include/boost/thread/pthread/shared_mutex.hpp:21: note: boost::shared_mutex::shared_mutex(boost::shared_mutex&)
如何解决？
也许我与升压互斥技能是没有那么强..你会怎么做？你能给我一些代码吗？ – St0rM
@ St0rM - 我会说它更适合需要工作的标准容器。如果你知道自己在做什么，在某些情况下可以将对象直接放入容器中。但是一般来说，你应该把**指向对象的指针放入一个容器**（像一个std :: map），**不是它们的对象**。容器可以在他们认为合适的情况下在内部复制对象，所以您无法控制何时调用构造函数和析构函数。 –
@TED：你一般并不意味着，你呢？容器中的指针通常不正确。 – GManNickG