extern mod rustrt { fn rust_dbg_call(cb: *u8, data: libc::uintptr_t) -> libc::uintptr_t; } extern fn cb(data: libc::uintptr_t) -> libc::uintptr_t { if data == 1u { data } else { count(data - 1u) + 1u } } fn count(n: uint) -> uint { debug!{"n = %?", n}; rustrt::rust_dbg_call(cb, n) } fn main() { let result = count(1000u); debug!{"result = %?", result}; assert result == 1000u; }