Function nc::fcntl

pub unsafe fn fcntl(fd: i32, cmd: i32, arg: usize) -> Result<i32, Errno>

manipulate file descriptor.

Example

let path = "/etc/passwd";
let ret = unsafe { nc::openat(nc::AT_FDCWD, path, nc::O_RDONLY, 0) };
assert!(ret.is_ok());
let fd = ret.unwrap();

let ret = unsafe { nc::fcntl(fd, nc::F_DUPFD, 0) };
assert!(ret.is_ok());
let fd2 = ret.unwrap();
let ret = unsafe { nc::close(fd) };
assert!(ret.is_ok());
let ret = unsafe { nc::close(fd2) };
assert!(ret.is_ok());