| [/ |
| / Copyright (c) 2003-2021 Christopher M. Kohlhoff (chris at kohlhoff dot com) |
| / |
| / Distributed under the Boost Software License, Version 1.0. (See accompanying |
| / file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt) |
| /] |
| |
| [section:OperationState Operation state concept] |
| |
| template<class O> |
| concept operation_state = |
| destructible<O> && |
| is_object_v<O> && |
| requires (O& o) { |
| { execution::start(o) } noexcept; |
| }; |
| |
| An object whose type satisfies `operation_state` represents the state of an |
| asynchronous operation. It is the result of calling `execution::connect` with a |
| `sender` and a `receiver`. |
| |
| `execution::start` may be called on an `operation_state` object at most once. |
| Once `execution::start` has been invoked, the caller shall ensure that the |
| start of a non-exceptional invocation of one of the receiver's |
| completion-signalling operations strongly happens before [intro.multithread] |
| the call to the `operation_state` destructor. |
| |
| The start of the invocation of `execution::start` shall strongly happen before |
| [intro.multithread] the invocation of one of the three receiver operations. |
| |
| `execution::start` may or may not block pending the successful transfer of |
| execution to one of the three receiver operations. |
| |
| [endsect] |
