Re: [Boost-users] How to convert std::string into basic_string

Subject: Re: [Boost-users] How to convert std::string into basic_string
From: manish4gupta (manish_at_[hidden])
Date: 2009-09-17 04:27:19

I am trying to store the index file (keyword , position) where keyword is
string while position is long. But before doing that i am doing some
benchmarking for the given code in  which map is created as key, value.
Where key is char_string (typedef of basic_string) but when i read the data
using C++, it will be string. So my intention is to convert string into
char_string. For that i am testing to convert std:: string s = "test"  into 
char_string. But getting the error message. Please do help me.

#include <boost/interprocess/managed_shared_memory.hpp>
#include <boost/interprocess/allocators/allocator.hpp>
#include <boost/interprocess/containers/map.hpp>
#include <boost/interprocess/containers/vector.hpp>
#include <boost/interprocess/containers/string.hpp>
#include <iostream>

using namespace boost::interprocess;

//Typedefs of allocators and containers
typedef managed_shared_memory::segment_manager                      
segment_manager_t;
typedef allocator<void, segment_manager_t>                          
void_allocator;
typedef allocator<int, segment_manager_t>                           
int_allocator;
typedef vector<int, int_allocator>                                  
int_vector;
typedef allocator<int_vector, segment_manager_t>                    
int_vector_allocator;
typedef vector<int_vector, int_vector_allocator>                    
int_vector_vector;
typedef allocator<char, segment_manager_t>                          
char_allocator;
typedef basic_string<char, std::char_traits<char>, char_allocator>  
char_string;

class complex_data
{
   int               id_;
   char_string       char_string_;
   int_vector_vector int_vector_vector_;

   public:
   //Since void_allocator is convertible to any other allocator<T>, we can
simplify
   //the initialization taking just one allocator for all inner containers.
   complex_data(int id, const char *name, const void_allocator &void_alloc)
      : id_(id), char_string_(name, void_alloc),
int_vector_vector_(void_alloc)
   {}
   //Other members...
};

//Definition of the map holding a string as key and complex_data as mapped
type
typedef std::pair<const char_string, int>                     
map_value_type;
typedef std::pair<char_string, int>                           
movable_to_map_value_type;
typedef allocator<map_value_type, segment_manager_t>                   
map_value_type_allocator;
typedef map< char_string, int
           , std::less<char_string>, map_value_type_allocator>         
complex_map_type;

int main ()
{
   //Remove shared memory on construction and destruction
   struct shm_remove
   {
      shm_remove() { shared_memory_object::remove("MySharedMemory"); }
      ~shm_remove(){ shared_memory_object::remove("MySharedMemory"); }
   } remover;

   //Create shared memory
   managed_shared_memory segment(create_only,"MySharedMemory", 65536);

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

   //Construct the shared memory map and fill it
   complex_map_type *mymap = segment.construct<complex_map_type>
      //(object name), (first ctor parameter, second ctor parameter)
         ("MyMap")(std::less<char_string>(), alloc_inst);

std::string s1("test");
char_string s2(s1.c_str());

 
   for(int i = 0; i < 100; ++i)
   {
      char_string  key_object(alloc_inst);
      map_value_type value(key_object, i);
      mymap->insert(value);
   }
   return 0;
}
 

Roland Bock-2 wrote:
> 
> Hi,
> 
> can you please send a small but complete sample code of what you are 
> trying (a bunch of includes and a main function, not more than a few
> lines)?
> 
> Regards,
> 
> Roland
> 
> manish4gupta wrote:
>> I have tried both but i am getting the following error message 
>> 
>> In constructor ‘boost::interprocess_container::basic_string<CharT,
>> Traits,
>> Alloc>::basic_string(const CharT*, const A&) [with CharT = char, Traits =
>> std::char_traits<char>, A = boost::interprocess::allocator<char,
>> boost::interprocess::segment_manager<char,
>> boost::interprocess::rbtree_best_fit<boost::interprocess::mutex_family,
>> boost::interprocess::offset_ptr<void>, 0u>,
>> boost::interprocess::iset_index>
>>> ]’:
>> run.cpp:63: error: no matching function for call to
>> ‘boost::interprocess::allocator<char,
>> boost::interprocess::segment_manager<char,
>> boost::interprocess::rbtree_best_fit<boost::interprocess::mutex_family,
>> boost::interprocess::offset_ptr<void>, 0u>,
>> boost::interprocess::iset_index>
>>> ::allocator()’
>> /usr/include/boost/interprocess/allocators/allocator.hpp:129: note:
>> candidates are: boost::interprocess::allocator<T,
>> SegmentManager>::allocator(const boost::interprocess::allocator<T,
>> SegmentManager>&) [with T = char, SegmentManager =
>> boost::interprocess::segment_manager<char,
>> boost::interprocess::rbtree_best_fit<boost::interprocess::mutex_family,
>> boost::interprocess::offset_ptr<void>, 0u>,
>> boost::interprocess::iset_index>]
>> /usr/include/boost/interprocess/allocators/allocator.hpp:124: note:                
>> boost::interprocess::allocator<T,
>> SegmentManager>::allocator(SegmentManager*) [with T = char,
>> SegmentManager =
>> boost::interprocess::segment_manager<char,
>> boost::interprocess::rbtree_best_fit<boost::interprocess::mutex_family,
>> boost::interprocess::offset_ptr<void>, 0u>,
>> boost::interprocess::iset_index>]
>> 
>> 
>> 
>> Igor R wrote:
>>>> This is ok but i have to convert string into boost string.
>>> You mean Boost.Interprocess string.
>>>
>>> std::string s1("test");
>>>
>>> char_string s2(s1.begin(), s1.end());
>>> or:
>>> char_string s2(s1.c_str());
>>> _______________________________________________
>>> Boost-users mailing list
>>> Boost-users_at_[hidden]
>>> http://lists.boost.org/mailman/listinfo.cgi/boost-users
>>>
>>>
>> 
> _______________________________________________
> Boost-users mailing list
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