impl Child

fn kill(&mut self) -> Result<()>

Forces the child process to exit. If the child has already exited, Ok(()) is returned.

The mapping to ErrorKinds is not part of the compatibility contract of the function.

This is equivalent to sending a SIGKILL on Unix platforms.

Examples

use std::process::Command;

let mut command = Command::new("yes");
if let Ok(mut child) = command.spawn() {
    child.kill().expect("process should be killed");
} else {
    println!("yes command didn't start");
}

fn id(&self) -> u32

Returns the OS-assigned process identifier associated with this child.

Examples

use std::process::Command;

let mut command = Command::new("ls");
if let Ok(child) = command.spawn() {
    println!("Child's ID is {}", child.id());
} else {
    println!("ls command didn't start");
}

fn wait(&mut self) -> Result<ExitStatus>

Waits for the child to exit completely, returning the status that it exited with. This function will continue to have the same return value after it has been called at least once.

The stdin handle to the child process, if any, will be closed before waiting. This helps avoid deadlock: it ensures that the child does not block waiting for input from the parent, while the parent waits for the child to exit.

Examples

use std::process::Command;

let mut command = Command::new("ls");
if let Ok(mut child) = command.spawn() {
    child.wait().expect("child should be running");
    println!("Child has finished its execution!");
} else {
    println!("ls command didn't start");
}

fn try_wait(&mut self) -> Result<Option<ExitStatus>>

Attempts to collect the exit status of the child if it has already exited.

This function will not block the calling thread and will only check to see if the child process has exited or not. If the child has exited then on Unix the process ID is reaped. This function is guaranteed to repeatedly return a successful exit status so long as the child has already exited.

If the child has exited, then Ok(Some(status)) is returned. If the exit status is not available at this time then Ok(None) is returned. If an error occurs, then that error is returned.

Note that unlike wait, this function will not attempt to drop stdin.

Examples

use std::process::Command;

let mut child = Command::new("ls").spawn()?;

match child.try_wait() {
    Ok(Some(status)) => println!("exited with: {status}"),
    Ok(None) => {
        println!("status not ready yet, let's really wait");
        let res = child.wait();
        println!("result: {res:?}");
    }
    Err(e) => println!("error attempting to wait: {e}"),
}
# std::io::Result::Ok(())

fn wait_with_output(self) -> Result<Output>

Simultaneously waits for the child to exit and collect all remaining output on the stdout/stderr handles, returning an Output instance.

The stdin handle to the child process, if any, will be closed before waiting. This helps avoid deadlock: it ensures that the child does not block waiting for input from the parent, while the parent waits for the child to exit.

By default, stdin, stdout and stderr are inherited from the parent. In order to capture the output into this Result<Output> it is necessary to create new pipes between parent and child. Use stdout(Stdio::piped()) or stderr(Stdio::piped()), respectively.

Examples

use std::process::{Command, Stdio};

let child = Command::new("/bin/cat")
    .arg("file.txt")
    .stdout(Stdio::piped())
    .spawn()
    .expect("child should spawn");

let output = child
    .wait_with_output()
    .expect("wait_with_output on child should succeed");

assert!(output.status.success());