Function nc::preadv2 [−][src]
pub fn preadv2(
fd: i32,
vec: &mut [iovec_t],
pos_l: usize,
pos_h: usize,
flags: rwf_t
) -> Result<ssize_t, Errno>
Expand description
Read from a file descriptor without changing file offset.
let path = "/etc/passwd";
let ret = nc::openat(nc::AT_FDCWD, path, nc::O_RDONLY, 0);
assert!(ret.is_ok());
let fd = ret.unwrap();
let mut buf = [[0_u8; 64]; 4];
let capacity = 4 * 64;
let mut iov = Vec::with_capacity(buf.len());
for ref mut item in (&mut buf).iter() {
iov.push(nc::iovec_t {
iov_len: item.len(),
iov_base: item.as_ptr() as usize,
});
}
let iov_len = iov.len();
let flags = 0;
let ret = nc::preadv2(fd, &mut iov, 0, iov_len - 1, flags);
assert!(ret.is_ok());
assert_eq!(ret, Ok(capacity as nc::ssize_t));
assert!(nc::close(fd).is_ok());