Function nc::dup3

pub fn dup3(oldfd: i32, newfd: i32, flags: i32) -> Result<(), Errno>

Save as dup2(), but can set the close-on-exec flag on newfd.

let path = "/tmp/nc-dup3-file";
let fd = nc::creat(path, 0o644);
assert!(fd.is_ok());
let fd = fd.unwrap();
let newfd = 8;
assert!(nc::dup3(fd, newfd, nc::O_CLOEXEC).is_ok());
assert!(nc::close(fd).is_ok());
assert!(nc::close(newfd).is_ok());
assert!(nc::unlink(path).is_ok());