truncate_args
{ .sy_narg = AS(truncate_args), .sy_call = (sy_call_t *)sys_truncate, .sy_auevent = AUE_TRUNCATE, .sy_flags = 0, .sy_thrcnt = SY_THR_STATIC }, /* 479 = truncate */
struct truncate_args *p = params;
sys_truncate(struct thread *td, struct truncate_args *uap)
int sys_truncate(struct thread *, struct truncate_args *);