Hi,
I am trying to create a unordered_map in shared memory using Boost
Interprocess library. Here, is the code, which I'm trying to use
(taking examples from Boost Interprocess documentation):
#include
#include
#include <functional>
#include
#include
#include <iostream>
#include <string>
#include
namespace bipc = boost::interprocess;
typedef bipc::allocator CharAllocator;
typedef bipc::basic_string ShmemString;
struct Person
{
int age;
ShmemString name;
double salary;
Person(int i,
double sal,
const char* s,
const char_allocator& a)
: age(i),
name(s, a),
salary(sal)
{
}
void print() {}
}
typedef ShmemString KeyType;
typedef Person MappedType;
typedef std::pair< KeyType, MappedType > MapPersonType;
typedef bipc::allocator< MapPersonType,
bipc::managed_shared_memory::segment_manager >
ShMemAllocator;
typedef boost::unordered_map< KeyType,
MappedType,
boost::hash<KeyType>,
std::equal_to<KeyType>,
ShMemAllocator >
PersonMap;
In the main reader program, I create a map in the shared memory and I
insert an object in this map:
int main()
{
bipc::managed_shared_memory segment(bipc::create_only, "MySharedMemory", 65536);
PersonMap *persons = segment.construct<PersonMap>("MyHashMap")
( 3, boost::hash<ShmemString>(), std::equal_to<ShmemString>()
, segment.get_allocator<MapPersonType>());
char_allocator alloc(segment.get_allocator<char>());
Person p1(20, 10000, "ABC", alloc);
persons->insert(MapPersonType(ShmemString("Person1", alloc), p1));
}
However, when I am trying to access the map in the reader program, I
need to use a syntax like
persons->at(ShmemString("H", segment.get_allocator<char>())).print();
However, I would prefer to do this with a std::string, which results
in compilation errors:
persons->at(std::string("H")).print();
Is it possible to write the above statement, i.e. accessing the map
allocated in shared memory with std::string?
Thanks.
