debug0 655 kern/kern_sysctl.c extern struct ctldebug debug0, debug1; debug0 661 kern/kern_sysctl.c &debug0, &debug1, &debug2, &debug3, &debug4, debug0 466 kern/vfs_syscalls.c struct ctldebug debug0 = { "syncprt", &syncprt }; debug0 656 sys/sysctl.h extern struct ctldebug debug0, debug1, debug2, debug3, debug4;