let pub @stdin: Option[Stdin]

A handle to the captured input stream of the child process.

let pub @stdout: Option[Stdout]

A handle to the captured output stream of the child process.

let pub @stderr: Option[Stderr]

A handle to the captured error stream of the child process.

fn pub try_wait -> Result[Option[ExitStatus], Error] {
  match sys.try_wait(@id) {
    case Ok(None) -> Result.Ok(Option.None)
    case Ok(Some(n)) -> Result.Ok(Option.Some(ExitStatus(n)))
    case Error(e) -> Result.Error(e)
  }
}

fn pub try_wait -> Result[Option[ExitStatus], Error]

Returns the exit status of the child process without blocking the calling process.

If the process is still running, an Option.None is returned. If the process exited, an Option.Some(ExitStatus) is returned.

This method doesn't close STDIN before waiting.

fn pub mut wait -> Result[ExitStatus, Error] {
  drop(@stdin := Option.None)
  sys.wait(@id).map(fn (v) { ExitStatus(v) })
}

fn pub mut wait -> Result[ExitStatus, Error]

Waits for the child process to finish running, and returns an ExitStatus containing the exit status.

The child's STDIN stream (if any) is closed before waiting, avoiding deadlocks caused by child processes waiting for input from the parent while the parent waits for the child to exit.

Note that if you try to read from STDOUT or STDERR before calling ChildProcess.wait without closing STDIN first, the parent process may still deadlock as the read might not return and thus prevent ChildProcess.wait from first closing STDIN.

To prevent this from happening, always make sure STDIN is closed before reading from STDOUT or STDERR if the read happens before a call to ChildProcess.wait.