Jason Sachs wrote:
does anyone have a simple example of a map in shared memory, where the
key is also in shared memory & not a simple "int"?
This example will go in the "quick guide for the impatient" section ASAP.
//////////////////////////////////////////////////////////////////////////////
//
// (C) Copyright Ion Gaztanaga 2006-2008. Distributed under the Boost
// Software License, Version 1.0. (See accompanying file
// LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
//
// See http://www.boost.org/libs/interprocess for documentation.
//
//////////////////////////////////////////////////////////////////////////////
#include
#include
//[doc_complex_map
#include
#include
#include
#include
#include
using namespace boost::interprocess;
//Typedefs of allocators and containers
typedef managed_shared_memory::segment_manager
segment_manager_t;
typedef allocator
void_allocator;
typedef allocator
int_allocator;
typedef vector
int_vector;
typedef allocator
int_vector_allocator;
typedef vector
int_vector_vector;
typedef allocator
char_allocator;
typedef basic_string
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
map_value_type;
typedef std::pair
movable_to_map_value_type;
typedef allocator
map_value_type_allocator;
typedef map< char_string, complex_data
, std::less, map_value_type_allocator>
complex_map_type;
int main ()
{
shared_memory_object::remove("MySharedMemory");
remove_shared_memory_on_destroy remove_on_destroy("MySharedMemory");
{
//Create shared memory
managed_shared_memory segment(create_only,"MySharedMemory", 65536);
//An allocator convertible to any allocator
type
void_allocator alloc_inst (segment.get_segment_manager());
//Construct the shared memory map and fill it
complex_map_type *mymap = segment.construct
//(object name), (first ctor parameter, second ctor parameter)
("MyMap")(std::less(), alloc_inst);
for(int i = 0; i < 100; ++i){
//Both key(string) and value(complex_data) need an allocator
in their constructors
char_string key_object(alloc_inst);
complex_data mapped_object(i, "default_name", alloc_inst);
map_value_type value(key_object, mapped_object);
//Modify values and insert them in the map
mymap->insert(value);
}
}
return 0;
}
//]
#include
