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Document number: N4046

Date: 2014-05-26

Executors and Asynchronous Operations

by Christopher Kohlhoff

Excerpt:

This proposal builds on the type traits defined in N4045 Library Foundations for Asynchronous Operations. This paper is intended as an alternative proposal to N3785 Executors and schedulers.

The type traits introduced in N4045 Library Foundations for Asynchronous Operations define an extensible asynchronous model that can support:

• Callbacks, where minimal runtime penalty is desirable.
• Futures, and not just std::future but also future classes supplied by other libraries.
• Coroutines or resumable functions, without adding new keywords to the language.

The library introduced in this paper applies this asynchronous model, and its design philosophy, to executors. Rather than a design that is restricted to runtime polymorphism, we can allow users to choose the approach that is appropriate to their use case.

Future work will aim to develop guidance on the development of asynchronous operations that participate in an executor-aware model, such as those that integrate operating system services, for example networking support.