PipeReader in std::io - Rust
Description: Read end of an anonymous pipe.

## PipeReader

# Struct PipeReader

1.87.0 · Source

    pub struct PipeReader(/* private fields */);

Expand description

Read end of an anonymous pipe.

## Implementations§

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### impl PipeReader

1.87.0 · Source

#### pub fn try_clone(&self) -> Result<Self>

Creates a new `PipeReader` instance that shares the same underlying file description.

##### §Examples

    use std::fs;
    use std::io::{pipe, Write};
    use std::process::Command;
    const NUM_SLOT: u8 = 2;
    const NUM_PROC: u8 = 5;
    const OUTPUT: &str = "work.txt";

    let mut jobs = vec![];
    let (reader, mut writer) = pipe()?;

    // Write NUM_SLOT characters the pipe.
    writer.write_all(&[b'|'; NUM_SLOT as usize])?;

    // Spawn several processes that read a character from the pipe, do some work, then
    // write back to the pipe. When the pipe is empty, the processes block, so only
    // NUM_SLOT processes can be working at any given time.
    for _ in 0..NUM_PROC {
        jobs.push(
            Command::new("bash")
                .args(["-c",
                    &format!(
                         "read -n 1\n\
                          echo -n 'x' >> '{OUTPUT}'\n\
                          echo -n '|'",
                    ),
                ])
                .stdin(reader.try_clone()?)
                .stdout(writer.try_clone()?)
                .spawn()?,
        );
    }

    // Wait for all jobs to finish.
    for mut job in jobs {
        job.wait()?;
    }

    // Check our work and clean up.
    let xs = fs::read_to_string(OUTPUT)?;
    fs::remove_file(OUTPUT)?;
    assert_eq!(xs, "x".repeat(NUM_PROC.into()));

## Trait Implementations§

1.87.0 · Source§

### impl AsFd for PipeReader

Available on (Unix or HermitCore or `target_os=trusty` or WASI or `target_os=motor`) and non-`target_os=trusty` only.
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#### fn as_fd(&self) -> BorrowedFd<'_>

Borrows the file descriptor. Read more
1.87.0 · Source§

### impl AsRawFd for PipeReader

Available on (Unix or HermitCore or `target_os=trusty` or WASI or `target_os=motor`) and non-`target_os=trusty` only.
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#### fn as_raw_fd(&self) -> RawFd

Extracts the raw file descriptor. Read more
1.87.0 · Source§

### impl Debug for PipeReader

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

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

### impl From<OwnedFd> for PipeReader

Available on (Unix or HermitCore or `target_os=trusty` or WASI or `target_os=motor`) and non-`target_os=trusty` only.
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#### fn from(owned_fd: OwnedFd) -> Self

Converts to this type from the input type.
1.87.0 · Source§

### impl From<PipeReader> for OwnedFd

Available on (Unix or HermitCore or `target_os=trusty` or WASI or `target_os=motor`) and non-`target_os=trusty` only.
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#### fn from(pipe: PipeReader) -> Self

Converts to this type from the input type.
1.87.0 · Source§

### impl From<PipeReader> for Stdio

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#### fn from(pipe: PipeReader) -> Self

Converts to this type from the input type.
1.87.0 · Source§

### impl FromRawFd for PipeReader

Available on (Unix or HermitCore or `target_os=trusty` or WASI or `target_os=motor`) and non-`target_os=trusty` only.
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#### unsafe fn from_raw_fd(raw_fd: RawFd) -> Self

Constructs a new instance of `Self` from the given raw file descriptor. Read more
1.87.0 · Source§

### impl IntoRawFd for PipeReader

Available on (Unix or HermitCore or `target_os=trusty` or WASI or `target_os=motor`) and non-`target_os=trusty` only.
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#### fn into_raw_fd(self) -> RawFd

Consumes this object, returning the raw underlying file descriptor. Read more
1.87.0 · Source§

### impl Read for &PipeReader

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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_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
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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
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
1.87.0 · Source§

### impl Read for PipeReader

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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_vectored(&mut self, bufs: &mut [IoSliceMut<'_>]) -> Result<usize>

Like `read`, except that it reads into a slice of buffers. Read more
Source§

#### 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
Source§

#### 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
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
Source§

#### 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
Source§

#### 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 PipeReader

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### impl RefUnwindSafe for PipeReader

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### impl Send for PipeReader

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### impl Sync for PipeReader

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### impl Unpin for PipeReader

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### impl UnwindSafe for PipeReader

## 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.