IPC SAP A Family of Object-Oriented Interfaces for Local and Remote Interprocess Communication

This is part of a series that describes techniques for encapsulating existing operating system (OS) interprocess communication (IPC) mechanisms within object-oriented C++ wrappers. This paper focuses on the IPC SAP (“InterProcess Communication Service Access Point”) C++ class categories. IPC SAP provides applications with a family of object-oriented service access points that encapsulate standard network programming interfaces such as BSD sockets [2], the System V transport layer interface (TLI) [3], SVR4 STREAM pipes [4], UNIX FIFOs [5], and Windows NT named pipes [6]. In turn, these network programming interfaces shield developers and applications from nonportable details of the underlying OS local and remote IPC mechanisms. IPC mechanisms include standard connectionoriented and connectionless protocols (such as TCP, UDP, and IPX/SPX) available in modern operating systems (such as BSD/SVR4 UNIX, Windows, Windows NT, and OS/2). IPC SAP utilizes object-oriented techniques and C++ features to provide a rich set of components that simplify the development of 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 and discusses their limitations; Section 4 presents the object-oriented design and implementation of IPC SAP and explains how it overcomes limitations with existing interfaces; Section 5 examines the object-oriented design of the C++ wrappers for sockets, TLI, STREAM pipes, and FIFOs in detail; Section 6 illustrates several examples that use IPC SAP to implement a client/server application; and Section 7 discusses the advantages and disadvantages of using C++ to develop object-oriented wrappers. 2 Network Programming Interfaces