The C Preprocessor - Macros

Node: Macros Next: Conditionals Prev: Header Files Up: Top

Macros

A macro is a sort of abbreviation which you can define once and then use later. There are many complicated features associated with macros in the C preprocessor.

Simple Macros Macros that always expand the same way.

Argument Macros Macros that accept arguments that are substituted
into the macro expansion.

Predefined Predefined macros that are always available.

Stringification Macro arguments converted into string constants.

Concatenation Building tokens from parts taken from macro arguments.

Undefining Cancelling a macro's definition.

Redefining Changing a macro's definition.

Macro Pitfalls Macros can confuse the unwary. Here we explain
several common problems and strange features.

Next: Conditionals Up: Top

Simple Macros	Macros that always expand the same way.
Argument Macros	Macros that accept arguments that are substituted into the macro expansion.
Predefined	Predefined macros that are always available.
Stringification	Macro arguments converted into string constants.
Concatenation	Building tokens from parts taken from macro arguments.
Undefining	Cancelling a macro's definition.
Redefining	Changing a macro's definition.
Macro Pitfalls	Macros can confuse the unwary. Here we explain several common problems and strange features.