的boost ::進程間::地圖 - 如何與basic_string的類型更新值

Question

我有以下代碼：

typedef managed_shared_memory::segment_manager segment_manager_t; 
    typedef allocator<void, segment_manager_t> void_allocator; 
    typedef allocator<char, segment_manager_t> char_allocator; 
    typedef basic_string<char, std::char_traits<char>, char_allocator> char_string; 
    typedef std::pair<const char_string, char_string> map_value_type; 
    typedef allocator<map_value_type, segment_manager_t> map_value_type_allocator; 
    typedef map< char_string, char_string, std::less<char_string>, map_value_type_allocator> complex_map_type; 

........ 

      managed_shared_memory segment(open_only,shm_name.c_str()); 

      //An allocator convertible to any allocator<T, segment_manager_t> type 
      void_allocator alloc_inst (segment.get_segment_manager()); 

       complex_map_type *myMap = segment.find_or_construct<complex_map_type>("myMap")(std::less<char_string>(), alloc_inst); 

       //Here I am trying to update value. Key exists in the map. 
       (*myMap)[char_string(key.c_str(), alloc_inst)] = char_string(val.c_str(), alloc_inst); 

任何人都可以給我的最後一行正確的語法？ 最後一行給我一個編譯錯誤。

在此先感謝您的幫助。

Answer 1

我已經得到了答案。

char_string key(var.c_str(), alloc_inst); 
complex_map_type::iterator it = myMap->find(key); 

if(it != myMap->end()) 
(*it).second = char_string(new_value.c_str(), alloc_inst);