I have a need in my work to copy firewall rules from a master router to several dozen other routers. So I wrote this program.
It copies all firewall FILTER, MANGLE and ADDRESS-LIST entries from the hard coded "MASTER" router to the router specified on the command line.
I started with the C API from the wiki by webasdf. I fixed the memory management and added several other routines.
This might be a good example for someone looking to get into programming the API in C.