Extended STL, Volume 1: Collections and Iterators

Chapter 25. A Map of the Environment

	Very few people are willing to change the way they work in order to make someone else’s life easier.
	--Ian Bicking

	Trying is the first step toward failure.
	--Homer Simpson, The Simpsons

Introduction

This chapter describes environment_map, the only associative collection covered in the book. It is a Façade over standard and nonstandard facilities to provide a standard interface and portable implementation with which the process environment block may be queried and manipulated in an STL-compliant manner.

Motivation

Most use of the system environment involves simply looking up the value, if any, for a variable of a given name. However, there are occasionally more involved uses. For example, one of my system tools, ...