Function nc::sendfile

pub unsafe fn sendfile(
    out_fd: i32,
    in_fd: i32,
    offset: Option<&mut off_t>,
    count: size_t,
) -> Result<ssize_t, Errno>

Transfer data between two file descriptors.

Examples

println!("S_IRUSR: {}", nc::S_IRUSR);
println!("S_IRGRP: {}", nc::S_IRGRP);

let in_filename = "/etc/passwd";
let out_filename = "/tmp/passwd.copy";

#[cfg(any(target_os = "linux", target_os = "android"))]
let in_fd = unsafe {
    nc::openat(nc::AT_FDCWD, in_filename, nc::O_RDONLY, 0).expect("Failed to open file!")
};

#[cfg(target_os = "freebsd")]
let in_fd = unsafe {
    nc::openat(nc::AT_FDCWD, in_filename, nc::O_RDONLY, 0).expect("Failed to open file!")
};

#[cfg(any(target_os = "linux", target_os = "android"))]
let out_fd = unsafe {
    nc::openat(
        nc::AT_FDCWD,
        out_filename,
        nc::O_WRONLY | nc::O_CREAT,
        nc::S_IRUSR | nc::S_IWUSR | nc::S_IRGRP | nc::S_IROTH,
    )
    .expect("Failed to open passwd copy file")
};

#[cfg(target_os = "freebsd")]
let out_fd = unsafe {
    nc::openat(
        nc::AT_FDCWD,
        out_filename,
        nc::O_WRONLY | nc::O_CREAT,
        nc::S_IRUSR | nc::S_IWUSR | nc::S_IRGRP | nc::S_IROTH,
    )
    .expect("Failed to open passwd copy file")
};

let mut stat = nc::stat_t::default();
unsafe { nc::fstat(in_fd, &mut stat).expect("Failed to get file stat!") };
println!("stat: {:?}", stat);

let count = stat.st_blksize as usize;
println!("count: {}", count);
let nread =
    unsafe { nc::sendfile(out_fd, in_fd, None, count).expect("Failed to call sendfile()") };
println!("nread: {}", nread);

unsafe {
    let _ = nc::close(in_fd);
    let _ = nc::close(out_fd);
}

let ret = unsafe { nc::unlinkat(nc::AT_FDCWD, out_filename, 0) };
assert!(ret.is_ok());