12e6ae1d3SChuanqi Xu //===----------------------------------------------------------------------===// 22e6ae1d3SChuanqi Xu // 32e6ae1d3SChuanqi Xu // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions. 42e6ae1d3SChuanqi Xu // See https://llvm.org/LICENSE.txt for license information. 52e6ae1d3SChuanqi Xu // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception 62e6ae1d3SChuanqi Xu // 72e6ae1d3SChuanqi Xu //===----------------------------------------------------------------------===// 82e6ae1d3SChuanqi Xu 92e6ae1d3SChuanqi Xu #ifndef _LIBCPP___COROUTINE_COROUTINE_TRAITS_H 102e6ae1d3SChuanqi Xu #define _LIBCPP___COROUTINE_COROUTINE_TRAITS_H 112e6ae1d3SChuanqi Xu 122e6ae1d3SChuanqi Xu #include <__config> 13fafed06bSNikolas Klauser #include <__type_traits/void_t.h> 142e6ae1d3SChuanqi Xu 152e6ae1d3SChuanqi Xu #if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER) 162e6ae1d3SChuanqi Xu # pragma GCC system_header 172e6ae1d3SChuanqi Xu #endif 182e6ae1d3SChuanqi Xu 194f15267dSNikolas Klauser #if _LIBCPP_STD_VER >= 20 202e6ae1d3SChuanqi Xu 212e6ae1d3SChuanqi Xu _LIBCPP_BEGIN_NAMESPACE_STD 222e6ae1d3SChuanqi Xu 232e6ae1d3SChuanqi Xu // [coroutine.traits] 242e6ae1d3SChuanqi Xu // [coroutine.traits.primary] 252e6ae1d3SChuanqi Xu // The header <coroutine> defined the primary template coroutine_traits such that 262e6ae1d3SChuanqi Xu // if ArgTypes is a parameter pack of types and if the qualified-id R::promise_type 272e6ae1d3SChuanqi Xu // is valid and denotes a type ([temp.deduct]), then coroutine_traits<R, ArgTypes...> 282e6ae1d3SChuanqi Xu // has the following publicly accessible memebr: 292e6ae1d3SChuanqi Xu // 302e6ae1d3SChuanqi Xu // using promise_type = typename R::promise_type; 312e6ae1d3SChuanqi Xu // 322e6ae1d3SChuanqi Xu // Otherwise, coroutine_traits<R, ArgTypes...> has no members. 332e6ae1d3SChuanqi Xu template <class _Tp, class = void> 342e6ae1d3SChuanqi Xu struct __coroutine_traits_sfinae {}; 352e6ae1d3SChuanqi Xu 362e6ae1d3SChuanqi Xu template <class _Tp> 37*9783f28cSLouis Dionne struct __coroutine_traits_sfinae< _Tp, __void_t<typename _Tp::promise_type> > { 382e6ae1d3SChuanqi Xu using promise_type = typename _Tp::promise_type; 392e6ae1d3SChuanqi Xu }; 402e6ae1d3SChuanqi Xu 412e6ae1d3SChuanqi Xu template <class _Ret, class... _Args> 42*9783f28cSLouis Dionne struct coroutine_traits : public __coroutine_traits_sfinae<_Ret> {}; 432e6ae1d3SChuanqi Xu 442e6ae1d3SChuanqi Xu _LIBCPP_END_NAMESPACE_STD 452e6ae1d3SChuanqi Xu 464f15267dSNikolas Klauser #endif // __LIBCPP_STD_VER >= 20 472e6ae1d3SChuanqi Xu 482e6ae1d3SChuanqi Xu #endif // _LIBCPP___COROUTINE_COROUTINE_TRAITS_H 49