[−][src]Trait tokio::io::AsyncSeekExt

pub trait AsyncSeekExt: AsyncSeek {
    fn seek(&mut self, pos: SeekFrom) -> Seek<'_, Self>ⓘ
Notable traits for Seek<'_, S>
impl<S: ?Sized, '_> Future for Seek<'_, S> where
    S: AsyncSeek + Unpin,     type Output = Result<u64>;

    where
        Self: Unpin,
    { ... }
}

An extension trait which adds utility methods to AsyncSeek types.

As a convenience, this trait may be imported using the prelude:

Examples

use std::io::{Cursor, SeekFrom};
use tokio::prelude::*;

#[tokio::main]
async fn main() -> io::Result<()> {
    let mut cursor = Cursor::new(b"abcdefg");

    // the `seek` method is defined by this trait
    cursor.seek(SeekFrom::Start(3)).await?;

    let mut buf = [0; 1];
    let n = cursor.read(&mut buf).await?;
    assert_eq!(n, 1);
    assert_eq!(buf, [b'd']);

    Ok(())
}

See [module][crate::io] documentation for more details.

Provided methods

fn seek(&mut self, pos: SeekFrom) -> Seek<'_, Self>ⓘ

Notable traits for Seek<'_, S>

impl<S: ?Sized, '_> Future for Seek<'_, S> where
    S: AsyncSeek + Unpin,  type Output = Result<u64>;
 where
    Self: Unpin, 

Creates a future which will seek an IO object, and then yield the new position in the object and the object itself.

In the case of an error the buffer and the object will be discarded, with the error yielded.

Examples

use tokio::fs::File;
use tokio::prelude::*;

use std::io::SeekFrom;

let mut file = File::open("foo.txt").await?;
file.seek(SeekFrom::Start(6)).await?;

let mut contents = vec![0u8; 10];
file.read_exact(&mut contents).await?;
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Implementors

impl<S: AsyncSeek + ?Sized> AsyncSeekExt for S[src]

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