All Allocator and PMR Facilities

All Allocator and PMR Facilities

A compact index of allocator-aware types, polymorphic memory resources, and allocation-adjacent standard facilities.

How to use this reference page

Use reference pages to confirm names, categories, nearby facilities, and the constraints that matter before writing or reviewing code.

Scan the top of the page first to identify the primary types, functions, or algorithm families involved.
Use the nearby-page links when your question is really about a companion header, related algorithm family, or broader subsystem.
Validate tricky behavior with a small compileable example before relying on memory for details like invalidation, ordering, allocation, or lifetime rules.

All Allocator and PMR Facilities

Core allocator vocabulary

std::allocator<T>
allocator-aware container model
allocator_traits

Polymorphic memory resources

std::pmr::memory_resource
std::pmr::polymorphic_allocator<T>
std::pmr::monotonic_buffer_resource
std::pmr::unsynchronized_pool_resource
std::pmr::synchronized_pool_resource
std::pmr::new_delete_resource
std::pmr::null_memory_resource

PMR aliases and common users

std::pmr::string
std::pmr::vector
std::pmr::unordered_map
other std::pmr::* container aliases

Adjacent allocation facilities

std::allocate_shared
std::allocate_shared_for_overwrite
uninitialized memory helpers from <memory>
low-level allocation support from <new>

Practical rules

Use default allocators unless allocation strategy is a measured bottleneck or architectural concern.
Use PMR when many objects should share a resource policy or arena lifetime.
Keep memory-resource lifetime rules explicit; resources usually outlive the objects that allocate from them.

Example in practice

#include <memory>

int main() {
    auto owner = std::make_unique<int>(42);
    auto shared = std::make_shared<int>(*owner);
    owner.reset();
    return *shared;
}