5
mam ten kod:std :: map of boost :: mutex z dziwnego zachowania
////
// 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();
}
To generuje następujący błąd. Z tego, co rozumiem (i mógłbym być tu całkiem nie w porządku) g ++ mówi mi, że muteks jest przekazywany jako wartość const ... I nie rozumiem dlaczego.
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&)
Jak rozwiązać ten problem?
Może moje umiejętności z muteksy przypominającego nie jest tak silna .. . Jak byś to zrobił ? Czy możesz dać mi jakiś kod? – St0rM
@ St0rM - Powiedziałbym, że jest to bardziej umiejętne ze standardowymi pojemnikami, które wymagają pracy. Istnieją sytuacje, w których można umieścić obiekty bezpośrednio w pojemniku, jeśli wiesz, co robisz. Ale generalnie powinieneś szukać ** umieszczania wskaźników na obiektach w pojemniku ** (jak std :: map), ** nie obiektów themsevles **. Kontenery mogą być kopiowane wewnątrz obiektów, zgodnie z ich potrzebami, więc nie masz żadnej kontroli nad tym, kiedy zostaną wywołane konstruktory i destruktory. –
@TED: Tak naprawdę nie masz na myśli, prawda? Wskaźniki w pojemnikach zwykle nie są poprawne. – GManNickG