Advanced Programming in the UNIX® Environment, Third Edition

7. Process Environment

7.1. Introduction

Before looking at the process control primitives in the next chapter, we need to examine the environment of a single process. In this chapter, we’ll see how the main function is called when the program is executed, how command-line arguments are passed to the new program, what the typical memory layout looks like, how to allocate additional memory, how the process can use environment variables, and various ways for the process to terminate. Additionally, we’ll look at the longjmp and setjmp functions and their interaction with the stack. We finish the chapter by examining the resource limits of a process.

7.2. main Function

A C program starts execution with a function called main. The prototype for ...