[comex]

A small observation: CoreFoundation typedefs CFTypeRef (the generic object type) to void * , rather than having obj * be a separate type as in this library. This lets you pass pointers to any CF type to functions that expect CFTypeRe without the ugly cast: it's unsafe, as you can pass a pointer to any type without the compiler complaining, but so is explicitly casting. If you're not going to go the void * route, it would be nice to provide some macro like obj(x) to safely cast only valid types to object.

Anyway, it's nice to see a portable, modern CF-like library, although of course it's too slow for some cases where code specialization is called for.

Edit: On the general subject of C data structures, in case anyone's interested, I wrote a little portable C header that provides minimal hash table functionality using macros, with a large amount of control - still generic, but totally opposite to the approach used by this library, much lower level. It's modeled after the BSD <sys/queue.h> header, provides three versions (open, closed, and a higher level version), and is completely undocumented, but I'm somewhat happy with it as a proof of concept. Just throwing it out there. https://github.com/comex/cbit/blob/master/hash.h