The C Preprocessor

Last revised July 1992, for GCC version 2

• Transformations Made Globally
• Preprocessor Commands
• Header Files
  • Uses of Header Files
  • The `#include' Command
  • How `#include' Works
  • Once-Only Include Files
• Inheritance and Header Files
• Macros
  • Simple Macros
  • Macros with Arguments
  • Predefined Macros
    • Standard Predefined Macros
    • Nonstandard Predefined Macros
  • Stringification
  • Concatenation
  • Undefining Macros
  • Redefining Macros
  • Pitfalls and Subtleties of Macros
    • Improperly Nested Constructs
    • Unintended Grouping of Arithmetic
    • Swallowing the Semicolon
    • Duplication of Side Effects
    • Self-Referential Macros
    • Separate Expansion of Macro Arguments
    • Cascaded Use of Macros
  • Newlines in Macro Arguments
• Conditionals
  • Why Conditionals are Used
  • Syntax of Conditionals
    • The `#if' Command
    • The `#else' Command
    • The `#elif' Command
  • Keeping Deleted Code for Future Reference
  • Conditionals and Macros
  • Assertions
  • The `#error' and `#warning' Commands
• Combining Source Files
• Miscellaneous Preprocessor Commands
• C Preprocessor Output
• Invoking the C Preprocessor
• Concept Index
• Index of Commands, Macros and Options