int sync_file_range(int, off_t, off_t, unsigned);
ssize_t vmsplice(int, const struct iovec *, size_t, unsigned);
ssize_t splice(int, off_t *, int, off_t *, size_t, unsigned);
int sync_file_range(int, off_t, off_t, unsigned);
ssize_t vmsplice(int, const struct iovec *, size_t, unsigned);
ssize_t splice(int, off_t *, int, off_t *, size_t, unsigned);