Fluent C

Chapter 5. Data Lifetime and Ownership

If we have a look at procedural programming languages like C, there are no native object-oriented mechanisms. This makes life harder to some extent, because most design guidance is tailored for object-oriented software (like the Gang of Four design patterns).

This chapter discusses patterns for how to structure your C program with object-like elements. For these object-like elements, the patterns put special focus on who is responsible for creating and destroying them—in other words, they put special focus on lifetime and ownership. This topic is especially important for C because C has no automatic destructor and no garbage collection mechanism, and thus special attention has to be paid to cleanup of resources.

However, what is an “object-like element” and what is the meaning of it for C? The term object is well defined for object-oriented programming languages, but for non-object-oriented programming languages it is not clear what the term object means. For C, a simple definition for object is the following:

“An object is a named region of storage.”

Kernighan and Ritchie

Usually such an object describes a related set of data that has an identity and properties and that is used to store representations of things found in the real world. In object-oriented programming, an object additionally has the capability of polymorphism and inheritance. The object-like elements described throughout this book do not address polymorphism or ...