copy_file_range

pub fn copy_file_range(fd_in: fd_t, off_in: ?*i64, fd_out: fd_t, off_out: ?*i64, len: usize, flags: u32) CopyFileRangeError!usize {
    const rc = std.c.copy_file_range(fd_in, off_in, fd_out, off_out, len, flags);
    switch (errno(rc)) {
        .SUCCESS => return @intCast(rc),
        .BADF => return error.BadFileFlags,
        .FBIG => return error.FileTooBig,
        .INTR => return error.Interrupted,
        .INVAL => return error.InvalidArguments,
        .IO => return error.InputOutput,
        .INTEGRITY => return error.CorruptedData,
        .ISDIR => return error.IsDir,
        .NOSPC => return error.NoSpaceLeft,
        else => |err| return unexpectedErrno(err),
    }
}