stdout in std::io - Rust
Description: Constructs a new handle to the standard output of the current process.

## stdout

# Function stdout

1.0.0 · Source

    pub fn stdout() -> Stdout ⓘ

Expand description

Constructs a new handle to the standard output of the current process.

Each handle returned is a reference to a shared global buffer whose access is synchronized via a mutex. If you need more explicit control over locking, see the `Stdout::lock` method.

By default, the handle is line-buffered when connected to a terminal, meaning it flushes automatically when a newline (`\n`) is encountered. For immediate output, you can manually call the `flush` method. When the handle goes out of scope, the buffer is automatically flushed.

#### §Note: Windows Portability Considerations

When operating in a console, the Windows implementation of this stream does not support non-UTF-8 byte sequences. Attempting to write bytes that are not valid UTF-8 will return an error.

In a process with a detached console, such as one using `#![windows_subsystem = "windows"]`, or in a child process spawned from such a process, the contained handle will be null. In such cases, the standard library’s `Read` and `Write` will do nothing and silently succeed. All other I/O operations, via the standard library or via raw Windows API calls, will fail.

## §Examples

Using implicit synchronization:

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

    fn main() -> io::Result<()> {
        io::stdout().write_all(b"hello world")?;

        Ok(())
    }

Using explicit synchronization:

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

    fn main() -> io::Result<()> {
        let stdout = io::stdout();
        let mut handle = stdout.lock();

        handle.write_all(b"hello world")?;

        Ok(())
    }

Ensuring output is flushed immediately:

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

    fn main() -> io::Result<()> {
        let mut stdout = io::stdout();
        stdout.write_all(b"hello, ")?;
        stdout.flush()?;                // Manual flush
        stdout.write_all(b"world!\n")?; // Automatically flushed
        Ok(())
    }