All Allocator Traits and Pointer Helpers

All Allocator Traits and Pointer Helpers

A compact scan page for allocator_traits, pointer access helpers, address utilities, and allocation-adjacent support types.

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 Traits and Pointer Helpers

Core allocator helpers

std::allocator_traits
propagation and rebinding-related nested types and traits
construct/destroy support through allocator-aware interfaces

Pointer and address helpers

std::addressof
std::to_address
pointer_traits

Allocation-adjacent utilities

std::allocator<T>
std::polymorphic_allocator<T> in the PMR namespace
std::allocate_shared
std::allocate_shared_for_overwrite

Practical rules

reach for these mostly in library, allocator, and generic infrastructure code rather than ordinary application code
prefer to_address over hand-written raw-pointer extraction from fancy pointers
let allocator_traits mediate allocator behavior instead of assuming a specific allocator interface shape

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;
}