All Vocabulary Types

All Vocabulary Types

A compact index of common standard vocabulary types used to express optionality, alternatives, errors, ownership, views, and generic values.

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 Vocabulary Types

Optional, alternative, and error-carrying values

std::optional<T>
std::variant<Ts...>
std::expected<T, E>
std::monostate

Generic holders and callable/value wrappers

std::any
std::function
std::reference_wrapper<T>
std::pair<T, U>
std::tuple<Ts...>

Text and range views

std::string_view
std::span<T>
std::mdspan

Ownership and lifetime vocabulary

std::unique_ptr<T>
std::shared_ptr<T>
std::weak_ptr<T>

Error and source context vocabulary

std::error_code
std::source_location

Practical rules

Prefer explicit vocabulary types over sentinel values and out-parameters.
Choose the narrowest type that matches the semantic contract.
Use named structs instead of tuples when field meaning matters more than compactness.

Example in practice

#include <optional>

std::optional<int> result(bool ok) {
    return ok ? std::optional<int>{42} : std::nullopt;
}