Metall  v0.28
A persistent memory allocator for data-centric analytics

This is an example of how to use a multi-level STL container, a vector of vectors, with Metall.

// Copyright 2019 Lawrence Livermore National Security, LLC and other Metall
// Project Developers. See the top-level COPYRIGHT file for details.
// SPDX-License-Identifier: (Apache-2.0 OR MIT)
// This is an example of container of containers (or multi-level containers)
// with Metall
#include <iostream>
#include <boost/container/scoped_allocator.hpp>
#include <boost/container/vector.hpp>
namespace bc = boost::container;
// Vector of int
using inner_vector_allocator_type = metall::manager::allocator_type<int>;
using inner_vector_type = bc::vector<int, inner_vector_allocator_type>;
// Vector of vectors with scoped allocator adaptor
// In multi-level containers, you have to use scoped_allocator_adaptor in the
// most outer container so that the inner containers obtain their allocator
// arguments from the outer containers's scoped_allocator_adaptor See:
using outer_vector_allocator_type = bc::scoped_allocator_adaptor<
using outer_vector_type =
bc::vector<inner_vector_type, outer_vector_allocator_type>;
int main() {
metall::manager manager(metall::create_only, "/tmp/datastore");
auto pvec = manager.construct<outer_vector_type>("vec-of-vecs")(
// In the following examples
// the inner vectors obtain their allocator arguments from the outer
// vector's scoped_allocator_adaptor
// Pattern 1
// Pattern 2
(*pvec)[1][0] = 2;
// Pattern 3
std::vector<int> local_row = {3, 4};
pvec->emplace_back(local_row.begin(), local_row.end());
metall::manager manager(metall::open_only, "/tmp/datastore");
auto pvec = manager.find<outer_vector_type>("vec-of-vecs").first;
// Check the result of pattern 1
std::cout << (*pvec)[0][0] << std::endl; // Will print out 1
// Check the result of pattern 2
std::cout << (*pvec)[1][0] << std::endl; // Will print out 2
// Check the results of pattern 3
std::cout << (*pvec)[2][0] << std::endl; // Will print out 3
std::cout << (*pvec)[2][1] << std::endl; // Will print out 4
return 0;
A generalized Metall manager class.
Definition: basic_manager.hpp:40
A STL compatible allocator.
Definition: stl_allocator.hpp:34
int main()
Definition: jgraph.cpp:24
boost::container::scoped_allocator_adaptor< OuterAlloc, InnerAlloc... > scoped_allocator_adaptor
An allocator which can be used with multilevel containers.
Definition: scoped_allocator.hpp:16
basic_manager<> manager
Default Metall manager class which is an alias of basic_manager with the default template parameters.
Definition: metall.hpp:34