 int) (err error) {  var _p0 unsafe.Pointer  if len(b) > 0 {   _p0 = unsafe.Pointer(&b[0])  } else {   _p0 = unsafe.Pointer(&_zero)  }  _, _, e0 := Syscall(SYS_MADVISE, uintptr(_p0), uintptr(len(b)), uintptr(