Function copy_file_range

pub unsafe fn copy_file_range(
    fd_in: i32,
    off_in: &mut i64,
    fd_out: i32,
    off_out: &mut i64,
    len: usize,
    flags: u32,
) -> Result<isize, i32> 

Available on crate feature dep_nc only.

Copy a range of data from one file to another.

Examples

let path_in = "/tmp/nc-copy-file-range.in";
let fd_in = unsafe { nc::openat(nc::AT_FDCWD, path_in, nc::O_RDWR | nc::O_CREAT, 0o644) };
assert!(fd_in.is_ok());
let fd_in = fd_in.unwrap();
let msg = b"Hello, rust";
let ret = unsafe { nc::write(fd_in, msg) };
assert_eq!(ret, Ok(msg.len() as nc::ssize_t));
let path_out = "/tmp/nc-copy-file-range.out";
let fd_out = unsafe { nc::openat(nc::AT_FDCWD, path_out, nc::O_WRONLY | nc::O_CREAT, 0o644) };
assert!(fd_out.is_ok());
let fd_out = fd_out.unwrap();
let mut off_in = 0;
let mut off_out = 0;
let copy_len = 64;
let ret = unsafe { nc::copy_file_range(fd_in, &mut off_in, fd_out, &mut off_out, copy_len, 0) };
println!("ret: {ret:?}");
assert!(ret.is_ok());
assert_eq!(ret, Ok(msg.len() as nc::ssize_t));
let ret = unsafe { nc::close(fd_in) };
assert!(ret.is_ok());
let ret = unsafe { nc::close(fd_out) };
assert!(ret.is_ok());
let ret = unsafe { nc::unlinkat(nc::AT_FDCWD, path_out, 0) };
assert!(ret.is_ok());
let ret = unsafe { nc::unlinkat(nc::AT_FDCWD, path_in, 0) };
assert!(ret.is_ok());