How To Use Named And Optional Parameters In C -

: The caller must still know the order or use "sentinel" values (like NULL ) to mark the end of the argument list. Summary of Techniques Supports Named? Supports Optional? Standard Requirement Standard Positional Struct + Initializer Yes (defaults to 0) C99 or later Variadic Macros Yes (via struct) C99 or later stdarg.h Yes (manual)

The most common way to simulate named parameters is to pass a single struct to a function. By using C99 designated initializers, you can specify values for specific members by name.

Struct members not explicitly initialized are automatically set to zero or NULL by the compiler, effectively making them "optional". Example Implementation: How to use named and optional parameters in C

To avoid typing the struct name and parentheses every time, you can wrap the function call in a variadic macro.

For a more "classic" C approach, you can use variadic functions, though these do not provide true named parameters and are harder to use safely. : The caller must still know the order

You explicitly name the struct members in the function call.

#include // Define a struct to hold "parameters" typedef struct { int width; int height; const char *title; // Optional (defaults to NULL) } WindowArgs; void create_window(WindowArgs args) { printf("Window: %s (%dx%d)\n", args.title ? args.title : "Untitled", args.width, args.height); } int main() { // Named and optional call using a compound literal create_window((WindowArgs){.width = 800, .height = 600}); // Changing order and including all fields create_window((WindowArgs){.title = "Game", .height = 1080, .width = 1920}); return 0; } Use code with caution. Copied to clipboard 2. Enhancing with Macros for Cleaner Syntax Example Implementation: To avoid typing the struct name

: Used to retrieve an indefinite number of arguments.