All Tuple and Pair Helpers

All Tuple and Pair Helpers

A compact index of pair and tuple construction, access, forwarding, concatenation, and apply-style helper 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 Tuple and Pair Helpers

Pair facilities

std::pair
std::make_pair
std::piecewise_construct

Tuple facilities

std::tuple
std::make_tuple
std::forward_as_tuple
std::tie
std::tuple_cat
std::apply
std::ignore

Access and metadata helpers

std::get<I>
std::get<T>
std::tuple_size
std::tuple_element

Practical rules

Use pairs and tuples for lightweight grouping when names are unnecessary.
Prefer named structs when field meaning matters to readers or API clarity.
forward_as_tuple preserves value categories and should be used deliberately.

Small worked example

#include <tuple>

int add(int a, int b) {
	return a + b;
}

int main() {
	auto args = std::make_tuple(20, 22);
	return std::apply(add, args);
}

That is the most practical tuple-helper pattern: collect arguments or data, then unpack them into a callable with std::apply.

Decision guide

use std::pair for small two-value returns where the meaning is obvious
use std::tuple for generic plumbing or helper layers, not as a substitute for clear domain models
use std::tie for unpacking into existing variables and std::ignore when one element is intentionally unused

Example in practice

#include <tuple>

int add(int a, int b) {
    return a + b;
}

int main() {
    auto args = std::make_tuple(20, 22);
    return std::apply(add, args);
}