crates/user/reading_and_writing/src/main.rs


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use std::io::{Read, Write};

fn main() -> Result<(), std::io::Error> {
  let mut file = std::fs::OpenOptions::new()
    .read(true)
    .write(true)
    .create(false)
    .open("\\??\\Example")?;

  file.write_all("Hello, World!".as_bytes())?;

  let mut data = vec![0u8; 4096];
  let size = file.read(&mut data)?;

  match std::str::from_utf8(&data[..size]) {
    Ok(s) => println!("read {} bytes from \"{}\"", size, s),
    _ => println!("read {} bytes: {:x?}", size, &data[..size]),
  }

  Ok(())
}