5.1. Introduction

In this chapter, we describe the standard I/O library. This library is specified by the ISO C standard because it has been implemented on many operating systems other than the UNIX System. Additional interfaces are defined as extensions to the ISO C standard by the Single UNIX Specification.

The standard I/O library handles such details as buffer allocation and performing I/O in optimal-sized chunks, obviating our need to worry about using the correct block size (as in Section 3.9). This makes the library easy to use, but at the same time introduces another set of problems if we're not cognizant of what's going on.

The standard I/O library was written by Dennis Ritchie around 1975. It was a major revision of the Portable I/O library written by Mike Lesk. Surprisingly, little has changed in the standard I/O library after 30 years.