C, a reference manual

About the book

This is a reference work about C, written for people who already write code and need precise answers about how the language is defined and how its standard library behaves. Harbison and Steele built the book around lookup. You arrive with a question about a declaration, an operator, a type conversion or a library function, and you find a compact answer.

The book covers the language proper and the standard library, and it pays attention to the gap between C as standardized and C as implemented by real compilers. That attention to portability is part of why it has stayed in print across several editions.

C has changed since the first edition, so the book's value depends on which one you hold. Later editions track later revisions of the language standard. An early printing reflects the C of its time and will not describe features added afterward. Check the edition before relying on it for anything version-specific.

How to read it

Approach it as a desk reference, not a course. Read the early material on lexical elements, types and declarations once to learn how the book is organized, then use the index and the structured sections when a concrete question comes up. The prose is dense and assumes familiarity with programming. Readers new to C will want a teaching text alongside it.

Watch how the book separates what the language requires from what a particular implementation may do. When a passage describes behavior as undefined or implementation-defined, that is the point of the entry. The examples are short and functional, meant to pin down a rule rather than to demonstrate style.

Who it suits

Programmers who already write C and want a compact companion for checking declarations, conversions and library calls will get the most from it. People maintaining older code, or moving between compilers and standards, will find the portability framing useful. Students in a systems or compilers course may value it as a secondary source once they have basic fluency. Complete beginners should start elsewhere.

Reading considerations

The main limitation is age and edition drift. C has been revised repeatedly, and a given printing describes the language as of its own moment. Confirm which edition you have and which standard it addresses before treating any statement as current. The manual also assumes prior knowledge, so it will not teach you to program. Treat it as a source to check against your compiler's documentation, not as the final word.