ioctl_userfaultfd(2) System Calls Manual ioctl_userfaultfd(2) ioctl_userfaultfd - (libc -lc) #include /* Definition of UFFD* constants */ #include int ioctl(int fd, int op, ...); ioctl(2) userfaultfd ( userfaultfd(2)) : ioctl(fd, op, argp); fd userfaultfd op argp op. ioctl(2) . UFFDIO_API UFFDIO_REGISTER UFFDIO_UNREGISTER userfaultfd. . . . UFFDIO_API(2const) UFFDIO_REGISTER(2const) UFFDIO_UNREGISTER(2const) UFFDIO_COPY(2const) UFFDIO_MOVE(2const) UFFDIO_ZEROPAGE(2const) UFFDIO_WAKE(2const) UFFDIO_WRITEPROTECT(2const) UFFDIO_CONTINUE(2const) UFFDIO_POISON(2const) 0. -1 errno . : EFAULT argp . EINVAL ( UFFDIO_API.) userfaultfd ( UFFDIO_API). . userfaultfd(2). ioctl(2), mmap(2), userfaultfd(2) linux.git/Documentation/admin-guide/mm/userfaultfd.rst 3 . . : . 6.18 8 2026 ioctl_userfaultfd(2)