BoostContainer

BoostContainer, also known as Boost.Container, is a C++ library within the Boost C++ Libraries that provides allocator-aware containers designed to complement the standard library by offering alternative container implementations and enhanced memory management. It supplies standard-like containers such as vector, string, list, deque, map, multimap, set, and multiset, along with specialized containers that emphasize memory efficiency, locality, and customizable allocation strategies.

The library includes notable containers such as small_vector, a vector-like container with inline storage to avoid heap allocations for small sizes; flat_map and flat_set, which store elements in a contiguous layout for cache-friendly access and fast lookups; and other variants that can be configured with different allocators. These containers expand the options available for memory-conscious or performance-critical programming.

A core feature is allocator-awareness; containers can be built with boost::container::allocator and can propagate allocators via scoped_allocator_adaptor. It also integrates with Boost.PMR (polymorphic memory resources) to enable custom memory resources, such as pool allocators or monotonic buffers, allowing fine-grained control over allocation behavior.

BoostContainer containers are designed to be compatible with the STL interface so they can be used as drop-in replacements in many cases, while offering improved performance characteristics for certain workloads and greater flexibility for allocator design. They are particularly suited to memory-constrained environments, high-performance computing, and applications requiring explicit memory management.

Notes and considerations include that some containers are optimized for specific usage patterns, so trade-offs in insertion/lookup complexity or memory layout may apply. Documentation provides guidance on allocator compatibility, resource management, and performance considerations.