ChildStderr in std::process - Rust
Description: A handle to a child process’s stderr.

## ChildStderr

# Struct ChildStderr

1.0.0 · Source

    pub struct ChildStderr { /* private fields */ }

Expand description

A handle to a child process’s stderr.

This struct is used in the `stderr` field on `Child`.

When an instance of `ChildStderr` is dropped, the `ChildStderr`’s underlying file handle will be closed.

## Trait Implementations§

1.16.0 · Source§

### impl Debug for ChildStderr

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

Formats the value using the given formatter. Read more
1.20.0 · Source§

### impl From<ChildStderr> for Stdio

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#### fn from(child: ChildStderr) -> Stdio

Converts a `ChildStderr` into a `Stdio`.

##### §Examples

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

    let reverse = Command::new("rev")
        .arg("non_existing_file.txt")
        .stderr(Stdio::piped())
        .spawn()
        .expect("failed reverse command");

    let cat = Command::new("cat")
        .arg("-")
        .stdin(reverse.stderr.unwrap()) // Converted into a Stdio here
        .output()
        .expect("failed echo command");

    assert_eq!(
        String::from_utf8_lossy(&cat.stdout),
        "rev: cannot open non_existing_file.txt: No such file or directory\n"
    );

1.0.0 · Source§

### impl Read for ChildStderr

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#### fn read(&mut self, buf: &mut [u8]) -> Result<usize>

Pull some bytes from this source into the specified buffer, returning how many bytes were read. Read more
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#### fn read_buf(&mut self, buf: BorrowedCursor<'_>) -> Result<()>

🔬This is a nightly-only experimental API. (`read_buf` #78485)
Pull some bytes from this source into the specified buffer. Read more
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#### fn read_vectored(&mut self, bufs: &mut [IoSliceMut<'_>]) -> Result<usize>

Like `read`, except that it reads into a slice of buffers. Read more
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#### fn is_read_vectored(&self) -> bool

🔬This is a nightly-only experimental API. (`can_vector` #69941)
Determines if this `Read`er has an efficient `read_vectored` implementation. Read more
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#### fn read_to_end(&mut self, buf: &mut Vec<u8>) -> Result<usize>

Reads all bytes until EOF in this source, placing them into `buf`. Read more
1.0.0 · Source§

#### fn read_to_string(&mut self, buf: &mut String) -> Result<usize>

Reads all bytes until EOF in this source, appending them to `buf`. Read more
1.6.0 · Source§

#### fn read_exact(&mut self, buf: &mut [u8]) -> Result<()>

Reads the exact number of bytes required to fill `buf`. Read more
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#### fn read_buf_exact(&mut self, cursor: BorrowedCursor<'_>) -> Result<()>

🔬This is a nightly-only experimental API. (`read_buf` #78485)
Reads the exact number of bytes required to fill `cursor`. Read more
1.0.0 · Source§

#### fn by_ref(&mut self) -> &mut Self
where Self: Sized,

Creates a “by reference” adapter for this instance of `Read`. Read more
1.0.0 · Source§

#### fn bytes(self) -> Bytes<Self> ⓘ
where Self: Sized,

Transforms this `Read` instance to an `Iterator` over its bytes. Read more
1.0.0 · Source§

#### fn chain<R: Read>(self, next: R) -> Chain<Self, R> ⓘ
where Self: Sized,

Creates an adapter which will chain this stream with another. Read more
1.0.0 · Source§

#### fn take(self, limit: u64) -> Take<Self> ⓘ
where Self: Sized,

Creates an adapter which will read at most `limit` bytes from it. Read more
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#### fn read_array<const N: usize>(&mut self) -> Result<[u8; N]>
where Self: Sized,

🔬This is a nightly-only experimental API. (`read_array` #148848)
Read and return a fixed array of bytes from this source. Read more

## Auto Trait Implementations§

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### impl Freeze for ChildStderr

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### impl RefUnwindSafe for ChildStderr

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### impl Send for ChildStderr

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### impl Sync for ChildStderr

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### impl Unpin for ChildStderr

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### impl UnwindSafe for ChildStderr

## 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, 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.