When would you use a macro instead of an inline function?

Prefer static inline functions for most cases — they provide type checking, evaluate arguments once, and are debuggable. Use macros only when you need something inline functions cannot do:

• Type-generic operations — a single MAX macro works with int, float, uint32_t without overloading (C has no function overloading).
• Stringification and token pasting — # and ## operators for generating code, enum-to-string tables (X-macros), or logging with __FILE__ and __LINE__.
• Compile-time constants — #define ARRAY_SIZE 64 for array dimensions (can't use a variable for static array sizes in C89).
• Conditional compilation — #ifdef, #ifndef, include guards.

MISRA C Rule 4.9 advises: use inline functions instead of function-like macros wherever possible.