The C Preprocessor

1. Overview
2. Header Files
3. Macros
4. Conditionals
5. Diagnostics
6. Line Control
7. Pragmas
8. Other Directives
9. Preprocessor Output
10. Traditional Mode
11. Implementation Details
12. Invocation
Index of Directives
Concept Index

 -- The Detailed Node Listing ---

Overview

1.1 Initial processing
1.2 Tokenization
1.3 The preprocessing language

Header Files

2.1 Include Syntax
2.2 Include Operation
2.3 Search Path
2.4 Once-Only Headers
2.5 Computed Includes
2.6 Wrapper Headers
2.7 System Headers

Macros

3.1 Object-like Macros
3.2 Function-like Macros
3.3 Macro Arguments
3.4 Stringification
3.5 Concatenation
3.6 Variadic Macros
3.7 Predefined Macros
3.8 Undefining and Redefining Macros
3.9 Macro Pitfalls

Predefined Macros

3.7.1 Standard Predefined Macros
3.7.2 Common Predefined Macros
3.7.3 System-specific Predefined Macros
3.7.4 C++ Named Operators

Macro Pitfalls

3.9.1 Misnesting
3.9.2 Operator Precedence Problems
3.9.3 Swallowing the Semicolon
3.9.4 Duplication of Side Effects
3.9.5 Self-Referential Macros
3.9.6 Argument Prescan
3.9.7 Newlines in Arguments

Conditionals

4.1 Conditional Uses
4.2 Conditional Syntax
4.3 Deleted Code

Conditional Syntax

4.2.1 Ifdef
4.2.2 If
4.2.3 Defined
4.2.4 Else
4.2.5 Elif

Implementation Details

11.1 Implementation-defined behavior
11.2 Implementation limits
11.3 Obsolete Features
11.4 Differences from previous versions

Obsolete Features

11.3.1 Assertions
11.3.2 Obsolete once-only headers
11.3.3 Miscellaneous obsolete features

Copyright (C) 1987, 1989, 1991, 1992, 1993, 1994, 1995, 1996, 1997, 1998, 1999, 2000, 2001 Free Software Foundation, Inc.

Permission is granted to copy, distribute and/or modify this document under the terms of the GNU Free Documentation License, Version 1.1 or any later version published by the Free Software Foundation. A copy of the license is included in the accompanying manual for GCC, in the section "GNU Free Documentation License". This manual contains no Invariant Sections. The Front-Cover Texts are (a) (see below), and the the Back-Cover Texts are (b) (see below).

(a) The FSF's Front-Cover Text is:

A GNU Manual

(b) The FSF's Back-Cover Text is:

You have freedom to copy and modify this GNU Manual, like GNU software. Copies published by the Free Software Foundation raise funds for GNU development.{}