Struct core2::io::Error

pub struct Error { /* private fields */ }

The error type for I/O operations of the Read, Write, Seek, and associated traits.

Errors mostly originate from the underlying OS, but custom instances of Error can be created with crafted error messages and a particular value of ErrorKind.

Implementations

impl Error

pub fn new(kind: ErrorKind, error: &'static str) -> Error

Creates a new I/O error from a known kind of error as well as an arbitrary error payload.

This function is used to generically create I/O errors which do not originate from the OS itself. The error argument is an arbitrary payload which will be contained in this Error.

Examples

use core2::io::{Error, ErrorKind};

// errors can be created from strings
let custom_error = Error::new(ErrorKind::Other, "oh no!");

// errors can also be created from other errors
let custom_error2 = Error::new(ErrorKind::Interrupted, custom_error.into_inner().unwrap());

pub fn get_ref(&self) -> Option<&&'static str>

Returns a reference to the inner error wrapped by this error (if any).

If this Error was constructed via new then this function will return Some, otherwise it will return None.

Examples

use core2::io::{Error, ErrorKind};

fn print_error(err: &Error) {
    if let Some(inner_err) = err.get_ref() {
        println!("Inner error: {:?}", inner_err);
    } else {
        println!("No inner error");
    }
}

#[cfg(feature = "std")]
fn emit_error() {
    // Will print "No inner error".
    print_error(&Error::from(std::io::Error::last_os_error()));
    // Will print "Inner error: ...".
    print_error(&Error::new(ErrorKind::Other, "oh no!"));
}

#[cfg(not(feature = "std"))]
fn emit_error() {
    // Will print "No inner error".
    print_error(&ErrorKind::Other.into());
    // Will print "Inner error: ...".
    print_error(&Error::new(ErrorKind::Other, "oh no!"));
}

fn main() {
    emit_error();
}

pub fn into_inner(self) -> Option<&'static str>

Consumes the Error, returning its inner error (if any).

If this Error was constructed via new then this function will return Some, otherwise it will return None.

Examples

use core2::io::{Error, ErrorKind};

fn print_error(err: Error) {
    if let Some(inner_err) = err.into_inner() {
        println!("Inner error: {}", inner_err);
    } else {
        println!("No inner error");
    }
}

#[cfg(feature = "std")]
fn emit_error() {
    // Will print "No inner error".
    print_error(std::io::Error::last_os_error().into());
    // Will print "Inner error: ...".
    print_error(Error::new(ErrorKind::Other, "oh no!"));
}

#[cfg(not(feature = "std"))]
fn emit_error() {
    // Will print "No inner error".
    print_error(ErrorKind::Other.into());
    // Will print "Inner error: ...".
    print_error(Error::new(ErrorKind::Other, "oh no!"));
}

fn main() {
    emit_error();
}

pub fn kind(&self) -> ErrorKind

Returns the corresponding ErrorKind for this error.

Examples

use core2::io::{Error, ErrorKind};

fn print_error(err: Error) {
    println!("{:?}", err.kind());
}

#[cfg(feature = "std")]
fn emit_error() {
    // Will print "Other".
    print_error(std::io::Error::last_os_error().into());
    // Will print "AddrInUse".
    print_error(Error::new(ErrorKind::AddrInUse, "oh no!"));
}

#[cfg(not(feature = "std"))]
fn emit_error() {
    // Will print "Other".
    print_error(ErrorKind::Other.into());
    // Will print "AddrInUse".
    print_error(Error::new(ErrorKind::AddrInUse, "oh no!"));
}

fn main() {
    emit_error();
}

Trait Implementations

impl Debug for Error

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

Formats the value using the given formatter.

impl Display for Error

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

Formats the value using the given formatter.

impl Error for Error

fn source(&self) -> Option<&(dyn Error + 'static)>

The lower-level source of this error, if any.

impl From<ErrorKind> for Error

Intended for use for errors not exposed to the user, where allocating onto the heap (for normal construction via Error::new) is too costly.

fn from(kind: ErrorKind) -> Error

Converts an ErrorKind into an Error.

This conversion allocates a new error with a simple representation of error kind.

Examples

use core2::io::{Error, ErrorKind};

let not_found = ErrorKind::NotFound;
let error = Error::from(not_found);
assert_eq!("entity not found", format!("{}", error));