#include <mp-coro/task.h>
Detailed Description
template<task_value_type T = void, typename Allocator = void>
class mp_coro::task< T, Allocator >
class mp_coro::task< T, Allocator >
Task that produces a value of type T: to get that value, simply await the task.
Tasks are lazy: they always suspend initially. Each task has an optional continuation (i.e. the coroutine that is waiting for the result of this task) that is resumed at the final suspend point.
- Template Parameters
-
T Type of the value returned. Allocator Has no effect.
- Example
task<> foo() {
co_return;
}
task<> bar() {
task<> f = foo();
co_await f;
}
Task that produces a value of type T: to get that value, simply await the task.
Definition: task.h:65
flowchart
start(( ))
subgraph bar
bar_coro_alloc["coroutine frame allocation\n
promise_type promise {};\npromise.get_return_object()"]
bar_coro_alloc --> call_foo["task<> f = foo();"]
await_f["co_await f;"]
await_f --> op_co_await["f.operator co_await()"]
awaiter_promise["task::awaiter a {f.promise}"]
op_co_await --> awaiter_promise
await_rdy["a.await_ready()"]
awaiter_promise --> await_rdy
await_rdy --> if_await_rdy{{"f.done()"}}
if_await_rdy -->|false| await_sus["a.await_suspend(bar)"]
if_await_rdy -->|true| await_rsm["a.await_resume()"]
await_sus --> await_sus_body["f.promise.continuation = bar\nreturn foo"]
await_rsm --> bar_ret_void["promise.return_void()"]
bar_ret_void --> destroy_f["f.~task()"]
destroy_f --> destroy_foo["foo.destroy()"]
destroy_foo --> bar_final_sus["promise.final_suspend()"]
end
subgraph foo
coro_alloc["coroutine frame allocation\npromise_type promise {};\npromise.get_return_object()"]
coro_alloc --> init_sus["co_await promise.initial_suspend()"]
co_ret["co_return;"]
co_ret --> ret_void["promise.return_void()"]
ret_void --> final_sus["promise.final_suspend()"]
final_sus --> final_sus_a["task::promise_type::final_awaiter a {}"]
final_sus_a --> final_await_sus["a.await_suspend(foo)"]
final_await_sus --> final_await_sus_body["return promise.continuation"]
end
end_(( ))
start --> bar_coro_alloc
call_foo -->|Function call| coro_alloc
init_sus -->|Suspend| await_f
await_sus_body -->|Symmetric Control Transfer| co_ret
final_await_sus_body -->|Symmetric Control Transfer| await_rsm
bar_final_sus --> end_
- Examples
- async_read_file.cpp, run_async.cpp, simple_async_tasks.cpp, simple_tasks.cpp, and sleep_for.cpp.
Collaboration diagram for task< T, Allocator >:Classes | |
| struct | awaiter |
| Awaiter type for awaiting the result of a task. More... | |
| struct | promise_type |
| Required promise type for coroutines returning a task. More... | |
Public Types | |
| using | value_type = T |
| The type of the value produced by this task. More... | |
Public Member Functions | |
| task (task &&)=default | |
| Move constructor. More... | |
| task & | operator= (task &&)=delete |
| Move assignment not allowed. More... | |
| awaiter_of< T > auto | operator co_await () const &noexcept |
| When awaited, sets the current coroutine as this task's continuation, and then resumes this task's coroutine. More... | |
| awaiter_of< const T & > auto | operator co_await () const &noexcept |
| awaiter_of< T && > auto | operator co_await () const &&noexcept |
Private Member Functions | |
| task (promise_type *promise) | |
| Private constructor used in promise_type::get_return_object. More... | |
Private Attributes | |
| promise_ptr< promise_type > | promise_ |
| An owning pointer to the promise object in the coroutine frame. More... | |
Related Functions | |
(Note that these are not member functions.) | |
| template<awaitable A> | |
| task< remove_rvalue_reference_t< await_result_t< A > > > | make_task (A &&awaitable) |
Member Typedef Documentation
◆ value_type
| using value_type = T |
Constructor & Destructor Documentation
◆ task() [1/2]
◆ task() [2/2]
|
inlineprivate |
Private constructor used in promise_type::get_return_object.
Member Function Documentation
◆ operator=()
◆ operator co_await() [1/3]
|
inlinenoexcept |
◆ operator co_await() [2/3]
|
inlinenoexcept |
◆ operator co_await() [3/3]
|
inlinenoexcept |
Friends And Related Function Documentation
◆ make_task()
|
related |
Member Data Documentation
◆ promise_
|
private |
The documentation for this class was generated from the following file:
