[coroutine.syn]

# 17 Language support library [[support]](./#support)

## 17.13 Coroutines [[support.coroutine]](support.coroutine#coroutine.syn)

### 17.13.2 Header <coroutine> synopsis [coroutine.syn]

[🔗](#header:%3ccoroutine%3e)

// all freestanding#include <compare> // see [[compare.syn]](compare.syn "17.12.1 Header <compare> synopsis")namespace std {// [[coroutine.traits]](coroutine.traits "17.13.3 Coroutine traits"), coroutine traitstemplate<class R, class... ArgTypes>struct coroutine_traits; // [[coroutine.handle]](coroutine.handle "17.13.4 Class template coroutine_­handle"), coroutine handletemplate<class Promise = void>struct coroutine_handle; // [[coroutine.handle.compare]](coroutine.handle.compare "17.13.4.8 Comparison operators"), comparison operatorsconstexpr bool operator==(coroutine_handle<> x, coroutine_handle<> y) noexcept; constexpr strong_ordering operator<=>(coroutine_handle<> x, coroutine_handle<> y) noexcept; // [[coroutine.handle.hash]](coroutine.handle.hash "17.13.4.9 Hash support"), hash supporttemplate<class T> struct hash; template<class P> struct hash<coroutine_handle<P>>; // [[coroutine.noop]](coroutine.noop "17.13.5 No-op coroutines"), no-op coroutinesstruct noop_coroutine_promise; template<> struct coroutine_handle<noop_coroutine_promise>; using noop_coroutine_handle = coroutine_handle<noop_coroutine_promise>;

 noop_coroutine_handle noop_coroutine() noexcept; // [[coroutine.trivial.awaitables]](coroutine.trivial.awaitables "17.13.6 Trivial awaitables"), trivial awaitablesstruct suspend_never; struct suspend_always;}