experimental_async.H File Reference

Opt-in experimental coroutine-friendly bridge over ThreadPool. More...

#include <ah-errors.H>
#include <thread_pool.H>

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Macros
#define	ALEPH_ENABLE_EXPERIMENTAL_ASYNC   0
#define	ALEPH_DETAIL_HAS_COROUTINE_HEADER   0
#define	ALEPH_HAS_EXPERIMENTAL_ASYNC   0

Detailed Description

Opt-in experimental coroutine-friendly bridge over ThreadPool.

This header intentionally keeps a very small scope. It does not attempt to redesign Aleph-w around coroutines or provide a full sender/receiver framework. Instead it offers:

• Aleph::experimental::scheduled_operation: a move-only awaitable result handle for work scheduled on a ThreadPool
• Aleph::experimental::schedule(): submit a callable to a pool and obtain a scheduled_operation

The bridge is disabled by default. To enable it, build or compile with ALEPH_ENABLE_EXPERIMENTAL_ASYNC=1 and a C++20 compiler that provides <coroutine>. When these conditions are not met, the header still defines ALEPH_HAS_EXPERIMENTAL_ASYNC as 0, but no experimental async API is declared.

Portability assessment for Aleph-w's current targets:

• GCC 11+ with -std=c++20 provides the coroutine support needed here
• Clang 14+ with -std=c++20 likewise supports this limited bridge
• below C++20 this header simply stays disabled; it does not introduce a new coroutine requirement for code that does not opt into the bridge
• MSVC remains outside Aleph-w's documented support matrix

Design constraints:

• completion resumes an awaiting coroutine on the worker thread that finishes the scheduled callable
• each scheduled_operation<T> has single-consumer semantics, like std::future<T>
• return-by-reference is intentionally rejected; return a value or std::reference_wrapper<T> instead

Example:

#include <experimental_async.H>
#include <thread_pool.H>
 
#if ALEPH_HAS_EXPERIMENTAL_ASYNC
Aleph::ThreadPool pool(4);
auto op = Aleph::experimental::schedule(pool, [] { return 42; });
int value = op.get();
(void) value;
#endif

See docs/experimental_async_bridge.md and Examples/experimental_async_example.cc.

Definition in file experimental_async.H.

Macro Definition Documentation

ALEPH_DETAIL_HAS_COROUTINE_HEADER

#define ALEPH_DETAIL_HAS_COROUTINE_HEADER   0

Definition at line 109 of file experimental_async.H.

ALEPH_ENABLE_EXPERIMENTAL_ASYNC

#define ALEPH_ENABLE_EXPERIMENTAL_ASYNC   0

Definition at line 94 of file experimental_async.H.

ALEPH_HAS_EXPERIMENTAL_ASYNC

#define ALEPH_HAS_EXPERIMENTAL_ASYNC   0

Definition at line 119 of file experimental_async.H.