Here's one I used in a GC implementation a while back. That last 'uint_8t obj[]' is used to hold the object that was actually allocated. struct meta_obj {

Here's one I used in a GC implementation a while back. That last 'uint_8t obj[]' is used to hold the object that was actually allocated. struct meta_obj {     meta_obj_type *next; // next object in our list     mark_type mark;     size_t size;     gc_type_def type_def; uint8_t obj[]; // contained object }; Or another (contrived) example: struct obj_type { obj_type_enum type; }; struct string_obj_type { obj_type_enum type; char *c; }; You start with a collection of obj_type pointers and cast them to the appropriate pointer type when you have identified the actual contained struct. Useful if you need to have a heterogeneous list of things.