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
13. Environment Variables
GNU Free Documentation License
Index of Directives
Option Index
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 Directives Within Macro Arguments
3.10 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

3.10.1 Misnesting
3.10.2 Operator Precedence Problems
3.10.3 Swallowing the Semicolon
3.10.4 Duplication of Side Effects
3.10.5 Self-Referential Macros
3.10.6 Argument Prescan
3.10.7 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

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