Struct async_std::process::Child

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pub struct Child {
    pub stdin: Option<ChildStdin>,
    pub stdout: Option<ChildStdout>,
    pub stderr: Option<ChildStderr>,
    /* private fields */
}
Available on unstable only.
Expand description

A spawned child process.

The process can be in running or exited state. Use status() or output() to wait for it to exit.

If the Child is dropped, the process keeps running in the background.

§Examples

Spawn a process and wait for it to complete:

use async_process::Command;

Command::new("cp").arg("a.txt").arg("b.txt").status().await?;

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§stdin: Option<ChildStdin>

The handle for writing to the child’s standard input (stdin), if it has been captured.

§stdout: Option<ChildStdout>

The handle for reading from the child’s standard output (stdout), if it has been captured.

§stderr: Option<ChildStderr>

The handle for reading from the child’s standard error (stderr), if it has been captured.

Implementations§

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impl Child

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pub fn id(&self) -> u32

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

§Examples
use async_process::Command;

let mut child = Command::new("ls").spawn()?;
println!("id: {}", child.id());
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pub fn kill(&mut self) -> Result<(), Error>

Forces the child process to exit.

If the child has already exited, an InvalidInput error is returned.

This is equivalent to sending a SIGKILL on Unix platforms.

§Examples
use async_process::Command;

let mut child = Command::new("yes").spawn()?;
child.kill()?;
println!("exit status: {}", child.status().await?);
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pub fn try_status(&mut self) -> Result<Option<ExitStatus>, Error>

Returns the exit status if the process has exited.

Unlike status(), this method will not drop the stdin handle.

§Examples
use async_process::Command;

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

match child.try_status()? {
    None => println!("still running"),
    Some(status) => println!("exited with: {}", status),
}
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pub fn status(&mut self) -> impl Future<Output = Result<ExitStatus, Error>>

Drops the stdin handle and waits for the process to exit.

Closing the stdin of the process helps avoid deadlocks. It ensures that the process does not block waiting for input from the parent process while the parent waits for the child to exit.

§Examples
use async_process::{Command, Stdio};

let mut child = Command::new("cp")
    .arg("a.txt")
    .arg("b.txt")
    .spawn()?;

println!("exit status: {}", child.status().await?);
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pub fn output(self) -> impl Future<Output = Result<Output, Error>>

Drops the stdin handle and collects the output of the process.

Closing the stdin of the process helps avoid deadlocks. It ensures that the process does not block waiting for input from the parent process while the parent waits for the child to exit.

In order to capture the output of the process, Command::stdout() and Command::stderr() must be configured with Stdio::piped().

§Examples
use async_process::{Command, Stdio};

let child = Command::new("ls")
    .stdout(Stdio::piped())
    .stderr(Stdio::piped())
    .spawn()?;

let out = child.output().await?;

Trait Implementations§

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impl Debug for Child

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fn fmt(&self, f: &mut Formatter<'_>) -> Result<(), Error>

Formats the value using the given formatter. Read more

Auto Trait Implementations§

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impl Freeze for Child

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impl RefUnwindSafe for Child

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impl Send for Child

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impl Sync for Child

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impl Unpin for Child

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impl UnwindSafe for Child

Blanket Implementations§

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impl<T> Any for T
where T: 'static + ?Sized,

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fn type_id(&self) -> TypeId

Gets the TypeId of self. Read more
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impl<T> Borrow<T> for T
where T: ?Sized,

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fn borrow(&self) -> &T

Immutably borrows from an owned value. Read more
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impl<T> BorrowMut<T> for T
where T: ?Sized,

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fn borrow_mut(&mut self) -> &mut T

Mutably borrows from an owned value. Read more
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impl<T> From<T> for T

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fn from(t: T) -> T

Returns the argument unchanged.

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impl<T> Instrument for T

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fn instrument(self, span: Span) -> Instrumented<Self>

Instruments this type with the provided Span, returning an Instrumented wrapper. Read more
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fn in_current_span(self) -> Instrumented<Self>

Instruments this type with the current Span, returning an Instrumented wrapper. Read more
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impl<T, U> Into<U> for T
where U: From<T>,

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fn into(self) -> U

Calls U::from(self).

That is, this conversion is whatever the implementation of From<T> for U chooses to do.

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impl<T, U> TryFrom<U> for T
where U: Into<T>,

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type Error = Infallible

The type returned in the event of a conversion error.
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fn try_from(value: U) -> Result<T, <T as TryFrom<U>>::Error>

Performs the conversion.
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impl<T, U> TryInto<U> for T
where U: TryFrom<T>,

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type Error = <U as TryFrom<T>>::Error

The type returned in the event of a conversion error.
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fn try_into(self) -> Result<U, <U as TryFrom<T>>::Error>

Performs the conversion.
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impl<T> WithSubscriber for T

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fn with_subscriber<S>(self, subscriber: S) -> WithDispatch<Self>
where S: Into<Dispatch>,

Attaches the provided Subscriber to this type, returning a WithDispatch wrapper. Read more
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fn with_current_subscriber(self) -> WithDispatch<Self>

Attaches the current default Subscriber to this type, returning a WithDispatch wrapper. Read more