Re: [boost] Futures

Subject: Re: [boost] Futures
From: Bjorn Reese (breese_at_[hidden])
Date: 2015-01-04 06:46:26

On 01/04/2015 11:25 AM, Thomas Heller wrote:

> What's the difference between async_result and a future? I am unable to find
> that in the ASIO documentation.

async_result is like a return type trait. In its generalized form in
Asio it supports callbacks, but has be specialized for futures and
coroutines. Other mechanisms can be added; for instance, Boost.Fiber
comes with an async_result specialization.

The important point with that design is that with async_result the
user of an asynchronous function gets to decide which mechanism to use.

Examples:

   // Callback
   socket.async_send(buffer, [] (error_code, size_t) { });

   // Future
   auto myfuture = socket.async_send(buffer, use_future);

   // Coroutine
   socket.async_send(buffer, yield);