I thought function pointers were a well known part of C. How long can you program C before needing to call qsort or similar? Or before you encounter (or creat

I thought function pointers were a well known part of C. How long can you program C before needing to call qsort or similar? Or before you encounter (or create) your own method table? GLib offers closures in C; I've never used them, though, and they don't look very convenient.