What are some tricks I can use with macros? [closed]

Answer 1

Struct literals with default values (that are not zero), using C99 variadic macros

struct Example {
   int from;
   int to;
   const char *name;
}

#define EXAMPLE(...) ((struct Example){.from=0, .to=INT_MAX, .name="", __VA_ARGS__})

using EXAMPLE(.name="test") uses the default values, except for the explicit override of name. This shadowing with later mentions of the same member is well-defined in the standard.