1.0.0[−][src]Struct std::io::Error
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
.
Methods
impl Error
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pub fn new<E>(kind: ErrorKind, error: E) -> Error where
E: Into<Box<dyn Error + Send + Sync>>,
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E: Into<Box<dyn Error + Send + Sync>>,
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 std::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);Run
pub fn last_os_error() -> Error
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Returns an error representing the last OS error which occurred.
This function reads the value of errno
for the target platform (e.g.
GetLastError
on Windows) and will return a corresponding instance of
Error
for the error code.
Examples
use std::io::Error; println!("last OS error: {:?}", Error::last_os_error());Run
pub fn from_raw_os_error(code: i32) -> Error
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Creates a new instance of an Error
from a particular OS error code.
Examples
On Linux:
use std::io; let error = io::Error::from_raw_os_error(22); assert_eq!(error.kind(), io::ErrorKind::InvalidInput);Run
On Windows:
use std::io; let error = io::Error::from_raw_os_error(10022); assert_eq!(error.kind(), io::ErrorKind::InvalidInput);Run
pub fn raw_os_error(&self) -> Option<i32>
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Returns the OS error that this error represents (if any).
If this Error
was constructed via last_os_error
or
from_raw_os_error
, then this function will return Some
, otherwise
it will return None
.
Examples
use std::io::{Error, ErrorKind}; fn print_os_error(err: &Error) { if let Some(raw_os_err) = err.raw_os_error() { println!("raw OS error: {:?}", raw_os_err); } else { println!("Not an OS error"); } } fn main() { // Will print "raw OS error: ...". print_os_error(&Error::last_os_error()); // Will print "Not an OS error". print_os_error(&Error::new(ErrorKind::Other, "oh no!")); }Run
pub fn get_ref(&self) -> Option<&(dyn Error + Send + Sync + 'static)>
1.3.0[src]
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 std::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"); } } fn main() { // Will print "No inner error". print_error(&Error::last_os_error()); // Will print "Inner error: ...". print_error(&Error::new(ErrorKind::Other, "oh no!")); }Run
pub fn get_mut(&mut self) -> Option<&mut (dyn Error + Send + Sync + 'static)>
1.3.0[src]
Returns a mutable 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 std::io::{Error, ErrorKind}; use std::{error, fmt}; use std::fmt::Display; #[derive(Debug)] struct MyError { v: String, } impl MyError { fn new() -> MyError { MyError { v: "oh no!".to_string() } } fn change_message(&mut self, new_message: &str) { self.v = new_message.to_string(); } } impl error::Error for MyError { fn description(&self) -> &str { &self.v } } impl Display for MyError { fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result { write!(f, "MyError: {}", &self.v) } } fn change_error(mut err: Error) -> Error { if let Some(inner_err) = err.get_mut() { inner_err.downcast_mut::<MyError>().unwrap().change_message("I've been changed!"); } err } fn print_error(err: &Error) { if let Some(inner_err) = err.get_ref() { println!("Inner error: {}", inner_err); } else { println!("No inner error"); } } fn main() { // Will print "No inner error". print_error(&change_error(Error::last_os_error())); // Will print "Inner error: ...". print_error(&change_error(Error::new(ErrorKind::Other, MyError::new()))); }Run
pub fn into_inner(self) -> Option<Box<dyn Error + Send + Sync>>
1.3.0[src]
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 std::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"); } } fn main() { // Will print "No inner error". print_error(Error::last_os_error()); // Will print "Inner error: ...". print_error(Error::new(ErrorKind::Other, "oh no!")); }Run
pub fn kind(&self) -> ErrorKind
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Returns the corresponding ErrorKind
for this error.
Examples
use std::io::{Error, ErrorKind}; fn print_error(err: Error) { println!("{:?}", err.kind()); } fn main() { // Will print "No inner error". print_error(Error::last_os_error()); // Will print "Inner error: ...". print_error(Error::new(ErrorKind::AddrInUse, "oh no!")); }Run
Trait Implementations
impl Error for Error
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fn description(&self) -> &str
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fn cause(&self) -> Option<&dyn Error>
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fn source(&self) -> Option<&(dyn Error + 'static)>
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fn backtrace(&self) -> Option<&Backtrace>
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impl From<NulError> for Error
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impl<W> From<IntoInnerError<W>> for Error
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fn from(iie: IntoInnerError<W>) -> Error
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impl From<ErrorKind> for Error
1.14.0[src]
Intended for use for errors not exposed to the user, where allocating onto the heap (for normal construction via Error::new) is too costly.
impl Debug for Error
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impl Display for Error
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Auto Trait Implementations
impl !UnwindSafe for Error
impl !RefUnwindSafe for Error
impl Unpin for Error
impl Send for Error
impl Sync for Error
Blanket Implementations
impl<T> From<T> for T
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impl<T, U> TryFrom<U> for T where
U: Into<T>,
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U: Into<T>,
type Error = Infallible
The type returned in the event of a conversion error.
fn try_from(value: U) -> Result<T, <T as TryFrom<U>>::Error>
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impl<T, U> Into<U> for T where
U: From<T>,
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U: From<T>,
impl<T, U> TryInto<U> for T where
U: TryFrom<T>,
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U: TryFrom<T>,
type Error = <U as TryFrom<T>>::Error
The type returned in the event of a conversion error.
fn try_into(self) -> Result<U, <U as TryFrom<T>>::Error>
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impl<T> Borrow<T> for T where
T: ?Sized,
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T: ?Sized,
impl<T> BorrowMut<T> for T where
T: ?Sized,
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T: ?Sized,
ⓘImportant traits for &'_ mut Ffn borrow_mut(&mut self) -> &mut T
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impl<T> Any for T where
T: 'static + ?Sized,
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T: 'static + ?Sized,
impl<T> ToString for T where
T: Display + ?Sized,
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T: Display + ?Sized,