The C Preprocessor

The C preprocessor implements the macro language used to transform C, C++, and Objective-C programs before they are compiled. It can also be useful on its own.

Contents:

• Copyright
• Overview
  • Character sets
  • Initial processing
  • Tokenization
  • The preprocessing language
• Header Files
  • Include Syntax
  • Include Operation
  • Search Path
  • Once-Only Headers
  • Alternatives to Wrapper #ifndef
  • Computed Includes
  • Wrapper Headers
  • System Headers
• Macros
  • Object-like Macros
  • Function-like Macros
  • Macro Arguments
  • Stringizing
  • Concatenation
  • Variadic Macros
  • Predefined Macros
    • Standard Predefined Macros
    • Common Predefined Macros
    • System-specific Predefined Macros
    • C++ Named Operators
  • Undefining and Redefining Macros
  • Directives Within Macro Arguments
  • Macro Pitfalls
    • Misnesting
    • Operator Precedence Problems
    • Swallowing the Semicolon
    • Duplication of Side Effects
    • Self-Referential Macros
    • Argument Prescan
    • Newlines in Arguments
• Conditionals
  • Conditional Uses
  • Conditional Syntax
    • Ifdef
    • If
    • Defined
    • Else
    • Elif
    • __has_attribute
    • __has_cpp_attribute
    • __has_c_attribute
    • __has_builtin
    • __has_include
  • Deleted Code
• Diagnostics
• Line Control
• Pragmas
• Other Directives
• Preprocessor Output
• Traditional Mode
  • Traditional lexical analysis
  • Traditional macros
  • Traditional miscellany
  • Traditional warnings
• Implementation Details
  • Implementation-defined behavior
  • Implementation limits
  • Obsolete Features
    • Assertions
• Invocation
  • Options
• Environment Variables
• GNU Free Documentation License
  • Preamble
  • 1. APPLICABILITY AND DEFINITIONS
  • 2. VERBATIM COPYING
  • 3. COPYING IN QUANTITY
  • 4. MODIFICATIONS
  • 5. COMBINING DOCUMENTS
  • 6. COLLECTIONS OF DOCUMENTS
  • 7. AGGREGATION WITH INDEPENDENT WORKS
  • 8. TRANSLATION
  • 9. TERMINATION
  • 10. FUTURE REVISIONS OF THIS LICENSE
  • 11. RELICENSING
  • ADDENDUM: How to use this License for your documents
• Indexes and tables
  • TODO