使用带有boost :: asio的期货 [英] Using futures with boost::asio

问题描述

有人能很好地指出使用带有>提升ASIO ?我有一个现有的异步库，该库使用回调函数，我想为其提供一个更友好的同步接口.

Does anyone have a good pointer to examples which use futures from the Boost thread library with Boost ASIO? I have an existing asynchronous library which uses callback function that I would like to provide a friendlier synchronous interface for.

推荐答案

在不了解与现有异步库之间的交互作用的情况下，很难提供一个简洁的解决方案.不过，此 answer 使用Boost.Future和Boost.Asio来实现Active Object模式.当创建将来 ，请考虑检查现有的异步库以确定哪种方法更合适:

It is difficult to provide a concise solution without understanding the interactions with the existing asynchronous library. Nevertheless, this answer uses Boost.Future and Boost.Asio to implement an Active Object pattern. When creating a future, consider examining the existing asynchronous library to determine which approach is more appropriate:

• boost :: packaged_task 提供了可以创建未来的函子.可以在Boost.Asio io_service 的上下文中执行此函子.为了与现有的异步库集成以及解决右值语义，可能还需要一些附加的包装级别.如果当前函数调用已返回该值，请考虑使用此方法.
• boost :: promise 提供了可以设置其值的较低级别的对象.可能需要修改需要接受 promise 作为参数的现有函数，并将其填充到函数中. promise 将绑定到提供给Boost.Asio io_service 的处理程序.与 boost :: packaged_task 一样，可能需要附加包装级别才能处理右值语义.

• boost::packaged_task provides a functor that can create a future. This functor can be executed within the context of Boost.Asio io_service. Some additional level of wrapping may be required to integrate with the existing asynchronous library, as well as work around rvalue semantics. Consider using this approach if the current function calls already return the value.
• boost::promise provides a lower level object which can have its value set. It may require modifying existing functions need to accept the promise as an argument, and populate it within the function. The promise would be bound to the handler that is provided to Boost.Asio io_service. As with boost::packaged_task, it may require an additional level of wrapping to deal with rvalue semantics.

最后，Boost.Asio 1.54(当前处于beta版)为

Finally, Boost.Asio 1.54 (currently in beta), provides first-class support for C++ futures. Here is the official example. Even if you are unable to currently use 1.54 beta, it may be beneficial to examine the interface and implementation.

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