How to Build a Generic min() Function in C Using _Generic

C lacks built-in templates, making a truly generic minimum function difficult to implement without macros that risk side effects or undefined behavior. A common workaround is to define multiple type-specific inline functions — such as min_ll, min_ull, min_d, and min_ld — each handling a category of numeric types. A helper macro using the ## token-pasting operator can reduce the repetitive boilerplate involved in writing these functions. C11's _Generic keyword can then wrap all these functions under a single min() macro that automatically selects the correct implementation based on the operands' common type. The (I) + (J) expression inside _Generic leverages standard arithmetic conversions, allowing smaller types like char and short to be promoted without needing explicit cases for each.