Variadic macro
A variadic macro is a function-like C preprocessor macro whose parameter list accepts a variable number of arguments through an ellipsis.
Modern C
A variadic macro is a C function-like macro whose parameter list accepts a variable number of arguments through an ellipsis.
- How it is used
- Uses variadic macros to build trace interfaces accepting a variable number of values.
- How deep it goes
- Works through argument forwarding, empty-list handling, stringification, counting, and array conversion; distinguishes these from variadic-function argument handling.
- Examples
- Builds tracing macros that print formatted values, accept messages without values, stringify expressions, and pass counted values through an array.
- What you can do after
- Build it from scratch: write a variadic trace macro and adapt it to handle calls with or without values.
Modern C, Third Edition
A variadic macro is a function-like C preprocessor macro that accepts a variable number of arguments through an ellipsis parameter.
- How it is used
- Uses variadic macros to build tracing and formatted-output interfaces with a variable number of arguments.
- How deep it goes
- Explains declaration syntax, expansion, empty-list handling, stringification, and token-pasting dispatch, while deferring complete implementation details.
- Examples
- Demonstrates TRACE_PRINT6, TRACE_PRINT8, formatted output, __VA_ARGS__ stringification, and fprintf dispatch macros.
- What you can do after
- Build it from scratch using ellipsis parameters, __VA_ARGS__, __VA_OPT__, stringification, and token pasting while avoiding empty-call errors.
Related concepts
- __VA_ARGS__uses · __VA_ARGS__ is the predefined C preprocessor identifier that expands to arguments supplied for a variadic macro’s ellipsis parameter.
- variadic argumentsalternative to · A variadic function or parameter accepts a variable number of arguments, often collecting the supplied values into a sequence of a specified type.
- function-like macrokind of · A function-like macro is a macro invoked with function-like syntax that accepts token input and expands or transforms it into generated source.
- __VA_OPT__uses · __VA_OPT__ is a C23 preprocessor feature that conditionally includes replacement tokens when a variadic macro receives one or more variable arguments.
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