| [/ |
| / Copyright (c) 2003-2010 Christopher M. Kohlhoff (chris at kohlhoff dot com) |
| / |
| / Distributed under the Boost Software License, Version 1.0. (See accompanying |
| / file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt) |
| /] |
| |
| [section:rationale Rationale] |
| |
| Most programs interact with the outside world in some way, whether it be via a |
| file, a network, a serial cable, or the console. Sometimes, as is the case with |
| networking, individual I/O operations can take a long time to complete. This |
| poses particular challenges to application development. |
| |
| Boost.Asio provides the tools to manage these long running operations, without |
| requiring programs to use concurrency models based on threads and explicit |
| locking. |
| |
| The Boost.Asio library is intended for programmers using C++ for systems programming, |
| where access to operating system functionality such as networking is often |
| required. In particular, Boost.Asio addresses the following goals: |
| |
| * [*Portability.] The library should support a range of commonly used operating |
| systems, and provide consistent behaviour across these operating systems. |
| |
| * [*Scalability.] The library should facilitate the development of network |
| applications that scale to thousands of concurrent connections. The library |
| implementation for each operating system should use the mechanism that best |
| enables this scalability. |
| |
| * [*Efficiency.] The library should support techniques such as scatter-gather |
| I/O, and allow programs to minimise data copying. |
| |
| * [*Model concepts from established APIs, such as BSD sockets.] The |
| BSD socket API is widely implemented and understood, and is covered in much |
| literature. Other programming languages often use a similar interface for |
| networking APIs. As far as is reasonable, Boost.Asio should leverage existing |
| practice. |
| |
| * [*Ease of use.] The library should provide a lower entry barrier for new |
| users by taking a toolkit, rather than framework, approach. That is, it should |
| try to minimise the up-front investment in time to just learning a few basic |
| rules and guidelines. After that, a library user should only need to understand |
| the specific functions that are being used. |
| |
| * [*Basis for further abstraction.] The library should permit the development |
| of other libraries that provide higher levels of abstraction. For example, |
| implementations of commonly used protocols such as HTTP. |
| |
| Although Boost.Asio started life focused primarily on networking, its concepts of |
| asynchronous I/O have been extended to include other operating system resources |
| such as serial ports, file descriptors, and so on. |
| |
| [endsect] |
