IPC SAP C++ Wrappers for Efficient, Portable, and Flexible Network Programming

This paper describes object-oriented (OO) techniques for encapsulating OS interprocess communication (IPC) mechanisms with C++ wrappers. The paper focuses on the C++ wrappers provided by the IPC SAP components in the ACE framework [2]. ACE is a collection of reusable C++ class libraries and OO framework components that simplify the development of portable, high-performance and real-time communication software. IPC SAP is a component in ACE that provides a family of OO network programming interfaces to encapsulate the Socket interface [3], the System V transport layer interface (TLI) [4], SVR4 STREAM pipes [5], UNIX FIFOs [6], and Windows NT named pipes [7]. The C++ wrappers in IPC SAP shield developers and applications from non-portable details of native OS local and remote IPC mechanisms. The IPC mechanisms encapsulated by IPC SAP include standard connection-oriented and connectionless protocols, such as TCP, UDP, and IPX/SPX, available in UNIX/POSIX, Win32, and real-time operating systems. IPC SAP utilizes OO techniques and C++ features to provide a rich set of components that simplify the development of efficient, portable, and flexible communication software. This paper is organized as follows: Section 2 outlines the levels of abstraction for programming communication software; Section 3 describes existing network programming interfaces; Section 4 outlines their limitations; Section 5 presents the OO design and implementation of IPC SAP and explains how it overcomes limitations with existing network programming interfaces; Section 6 examines the OO design of the C++ wrappers for Sockets, TLI, STREAM pipes, and FIFOs in detail; Section 7 illustrates several examples that use IPC SAP to implement a client/server streaming application; Section 8 discusses the principles the guided the design of IPC SAP; and Section 9 summarizes the advantages and disadvantages of using C++ to develop OO wrappers for native OS interfaces.