Programming in C: A Practical Approach, First Edition

7

Scope, Linkage, Lifetime and Storage Classes

Learning Objectives

In this chapter, you will learn about:

• Scope and visibility of an identifier

• Local variables and global variables

• Linkage

• Different types of linkages in C

• The lifetime of an object

• Different storage classes

• How to allocate memory at the run time

7.1 Introduction

In the previous chapters, we have learnt about how to declare variables within a function and have seen that the amount of memory allocated to a variable depends upon its data type. We have restricted our discussion to the declaration of variables within a function (i.e. local variables) and have not discussed about the global variables (i.e. variables declared outside all the function definitions). The issues ...