4 #[cfg(target_pointer_width = "64")]
6 #[cfg(target_pointer_width = "64")]
7 use repr_bitpacked::Repr;
9 #[cfg(not(target_pointer_width = "64"))]
11 #[cfg(not(target_pointer_width = "64"))]
12 use repr_unpacked::Repr;
14 use crate::convert::From;
20 /// A specialized [`Result`] type for I/O operations.
22 /// This type is broadly used across [`std::io`] for any operation which may
25 /// This typedef is generally used to avoid writing out [`io::Error`] directly and
26 /// is otherwise a direct mapping to [`Result`].
28 /// While usual Rust style is to import types directly, aliases of [`Result`]
29 /// often are not, to make it easier to distinguish between them. [`Result`] is
30 /// generally assumed to be [`std::result::Result`][`Result`], and so users of this alias
31 /// will generally use `io::Result` instead of shadowing the [prelude]'s import
32 /// of [`std::result::Result`][`Result`].
34 /// [`std::io`]: crate::io
35 /// [`io::Error`]: Error
36 /// [`Result`]: crate::result::Result
37 /// [prelude]: crate::prelude
41 /// A convenience function that bubbles an `io::Result` to its caller:
46 /// fn get_string() -> io::Result<String> {
47 /// let mut buffer = String::new();
49 /// io::stdin().read_line(&mut buffer)?;
54 #[stable(feature = "rust1", since = "1.0.0")]
55 pub type Result<T> = result::Result<T, Error>;
57 /// The error type for I/O operations of the [`Read`], [`Write`], [`Seek`], and
58 /// associated traits.
60 /// Errors mostly originate from the underlying OS, but custom instances of
61 /// `Error` can be created with crafted error messages and a particular value of
64 /// [`Read`]: crate::io::Read
65 /// [`Write`]: crate::io::Write
66 /// [`Seek`]: crate::io::Seek
67 #[stable(feature = "rust1", since = "1.0.0")]
72 #[stable(feature = "rust1", since = "1.0.0")]
73 impl fmt::Debug for Error {
74 fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
75 fmt::Debug::fmt(&self.repr, f)
79 // Only derive debug in tests, to make sure it
80 // doesn't accidentally get printed.
81 #[cfg_attr(test, derive(Debug))]
85 SimpleMessage(&'static SimpleMessage),
89 // `#[repr(align(4))]` is probably redundant, it should have that value or
90 // higher already. We include it just because repr_bitpacked.rs's encoding
91 // requires an alignment >= 4 (note that `#[repr(align)]` will not reduce the
92 // alignment required by the struct, only increase it).
94 // If we add more variants to ErrorData, this can be increased to 8, but it
95 // should probably be behind `#[cfg_attr(target_pointer_width = "64", ...)]` or
96 // whatever cfg we're using to enable the `repr_bitpacked` code, since only the
97 // that version needs the alignment, and 8 is higher than the alignment we'll
98 // have on 32 bit platforms.
100 // (For the sake of being explicit: the alignment requirement here only matters
101 // if `error/repr_bitpacked.rs` is in use — for the unpacked repr it doesn't
105 pub(crate) struct SimpleMessage {
107 message: &'static str,
111 pub(crate) const fn new(kind: ErrorKind, message: &'static str) -> Self {
112 Self { kind, message }
116 /// Create and return an `io::Error` for a given `ErrorKind` and constant
117 /// message. This doesn't allocate.
118 pub(crate) macro const_io_error($kind:expr, $message:expr $(,)?) {
119 $crate::io::error::Error::from_static_message({
120 const MESSAGE_DATA: $crate::io::error::SimpleMessage =
121 $crate::io::error::SimpleMessage::new($kind, $message);
126 // As with `SimpleMessage`: `#[repr(align(4))]` here is just because
127 // repr_bitpacked's encoding requires it. In practice it almost certainly be
128 // already be this high or higher.
133 error: Box<dyn error::Error + Send + Sync>,
136 /// A list specifying general categories of I/O error.
138 /// This list is intended to grow over time and it is not recommended to
139 /// exhaustively match against it.
141 /// It is used with the [`io::Error`] type.
143 /// [`io::Error`]: Error
144 #[derive(Clone, Copy, Debug, Eq, Hash, Ord, PartialEq, PartialOrd)]
145 #[stable(feature = "rust1", since = "1.0.0")]
149 /// An entity was not found, often a file.
150 #[stable(feature = "rust1", since = "1.0.0")]
152 /// The operation lacked the necessary privileges to complete.
153 #[stable(feature = "rust1", since = "1.0.0")]
155 /// The connection was refused by the remote server.
156 #[stable(feature = "rust1", since = "1.0.0")]
158 /// The connection was reset by the remote server.
159 #[stable(feature = "rust1", since = "1.0.0")]
161 /// The remote host is not reachable.
162 #[unstable(feature = "io_error_more", issue = "86442")]
164 /// The network containing the remote host is not reachable.
165 #[unstable(feature = "io_error_more", issue = "86442")]
167 /// The connection was aborted (terminated) by the remote server.
168 #[stable(feature = "rust1", since = "1.0.0")]
170 /// The network operation failed because it was not connected yet.
171 #[stable(feature = "rust1", since = "1.0.0")]
173 /// A socket address could not be bound because the address is already in
175 #[stable(feature = "rust1", since = "1.0.0")]
177 /// A nonexistent interface was requested or the requested address was not
179 #[stable(feature = "rust1", since = "1.0.0")]
181 /// The system's networking is down.
182 #[unstable(feature = "io_error_more", issue = "86442")]
184 /// The operation failed because a pipe was closed.
185 #[stable(feature = "rust1", since = "1.0.0")]
187 /// An entity already exists, often a file.
188 #[stable(feature = "rust1", since = "1.0.0")]
190 /// The operation needs to block to complete, but the blocking operation was
191 /// requested to not occur.
192 #[stable(feature = "rust1", since = "1.0.0")]
194 /// A filesystem object is, unexpectedly, not a directory.
196 /// For example, a filesystem path was specified where one of the intermediate directory
197 /// components was, in fact, a plain file.
198 #[unstable(feature = "io_error_more", issue = "86442")]
200 /// The filesystem object is, unexpectedly, a directory.
202 /// A directory was specified when a non-directory was expected.
203 #[unstable(feature = "io_error_more", issue = "86442")]
205 /// A non-empty directory was specified where an empty directory was expected.
206 #[unstable(feature = "io_error_more", issue = "86442")]
208 /// The filesystem or storage medium is read-only, but a write operation was attempted.
209 #[unstable(feature = "io_error_more", issue = "86442")]
211 /// Loop in the filesystem or IO subsystem; often, too many levels of symbolic links.
213 /// There was a loop (or excessively long chain) resolving a filesystem object
214 /// or file IO object.
216 /// On Unix this is usually the result of a symbolic link loop; or, of exceeding the
217 /// system-specific limit on the depth of symlink traversal.
218 #[unstable(feature = "io_error_more", issue = "86442")]
220 /// Stale network file handle.
222 /// With some network filesystems, notably NFS, an open file (or directory) can be invalidated
223 /// by problems with the network or server.
224 #[unstable(feature = "io_error_more", issue = "86442")]
225 StaleNetworkFileHandle,
226 /// A parameter was incorrect.
227 #[stable(feature = "rust1", since = "1.0.0")]
229 /// Data not valid for the operation were encountered.
231 /// Unlike [`InvalidInput`], this typically means that the operation
232 /// parameters were valid, however the error was caused by malformed
235 /// For example, a function that reads a file into a string will error with
236 /// `InvalidData` if the file's contents are not valid UTF-8.
238 /// [`InvalidInput`]: ErrorKind::InvalidInput
239 #[stable(feature = "io_invalid_data", since = "1.2.0")]
241 /// The I/O operation's timeout expired, causing it to be canceled.
242 #[stable(feature = "rust1", since = "1.0.0")]
244 /// An error returned when an operation could not be completed because a
245 /// call to [`write`] returned [`Ok(0)`].
247 /// This typically means that an operation could only succeed if it wrote a
248 /// particular number of bytes but only a smaller number of bytes could be
251 /// [`write`]: crate::io::Write::write
253 #[stable(feature = "rust1", since = "1.0.0")]
255 /// The underlying storage (typically, a filesystem) is full.
257 /// This does not include out of quota errors.
258 #[unstable(feature = "io_error_more", issue = "86442")]
260 /// Seek on unseekable file.
262 /// Seeking was attempted on an open file handle which is not suitable for seeking - for
263 /// example, on Unix, a named pipe opened with `File::open`.
264 #[unstable(feature = "io_error_more", issue = "86442")]
266 /// Filesystem quota was exceeded.
267 #[unstable(feature = "io_error_more", issue = "86442")]
268 FilesystemQuotaExceeded,
269 /// File larger than allowed or supported.
271 /// This might arise from a hard limit of the underlying filesystem or file access API, or from
272 /// an administratively imposed resource limitation. Simple disk full, and out of quota, have
273 /// their own errors.
274 #[unstable(feature = "io_error_more", issue = "86442")]
276 /// Resource is busy.
277 #[unstable(feature = "io_error_more", issue = "86442")]
279 /// Executable file is busy.
281 /// An attempt was made to write to a file which is also in use as a running program. (Not all
282 /// operating systems detect this situation.)
283 #[unstable(feature = "io_error_more", issue = "86442")]
285 /// Deadlock (avoided).
287 /// A file locking operation would result in deadlock. This situation is typically detected, if
288 /// at all, on a best-effort basis.
289 #[unstable(feature = "io_error_more", issue = "86442")]
291 /// Cross-device or cross-filesystem (hard) link or rename.
292 #[unstable(feature = "io_error_more", issue = "86442")]
294 /// Too many (hard) links to the same filesystem object.
296 /// The filesystem does not support making so many hardlinks to the same file.
297 #[unstable(feature = "io_error_more", issue = "86442")]
299 /// Filename too long.
301 /// The limit might be from the underlying filesystem or API, or an administratively imposed
303 #[unstable(feature = "io_error_more", issue = "86442")]
305 /// Program argument list too long.
307 /// When trying to run an external program, a system or process limit on the size of the
308 /// arguments would have been exceeded.
309 #[unstable(feature = "io_error_more", issue = "86442")]
311 /// This operation was interrupted.
313 /// Interrupted operations can typically be retried.
314 #[stable(feature = "rust1", since = "1.0.0")]
317 /// This operation is unsupported on this platform.
319 /// This means that the operation can never succeed.
320 #[stable(feature = "unsupported_error", since = "1.53.0")]
323 // ErrorKinds which are primarily categorisations for OS error
324 // codes should be added above.
326 /// An error returned when an operation could not be completed because an
327 /// "end of file" was reached prematurely.
329 /// This typically means that an operation could only succeed if it read a
330 /// particular number of bytes but only a smaller number of bytes could be
332 #[stable(feature = "read_exact", since = "1.6.0")]
335 /// An operation could not be completed, because it failed
336 /// to allocate enough memory.
337 #[stable(feature = "out_of_memory_error", since = "1.54.0")]
340 // "Unusual" error kinds which do not correspond simply to (sets
341 // of) OS error codes, should be added just above this comment.
342 // `Other` and `Uncategorised` should remain at the end:
344 /// A custom error that does not fall under any other I/O error kind.
346 /// This can be used to construct your own [`Error`]s that do not match any
349 /// This [`ErrorKind`] is not used by the standard library.
351 /// Errors from the standard library that do not fall under any of the I/O
352 /// error kinds cannot be `match`ed on, and will only match a wildcard (`_`) pattern.
353 /// New [`ErrorKind`]s might be added in the future for some of those.
354 #[stable(feature = "rust1", since = "1.0.0")]
357 /// Any I/O error from the standard library that's not part of this list.
359 /// Errors that are `Uncategorized` now may move to a different or a new
360 /// [`ErrorKind`] variant in the future. It is not recommended to match
361 /// an error against `Uncategorized`; use a wildcard match (`_`) instead.
362 #[unstable(feature = "io_error_uncategorized", issue = "none")]
368 pub(crate) fn as_str(&self) -> &'static str {
370 // Strictly alphabetical, please. (Sadly rustfmt cannot do this yet.)
372 AddrInUse => "address in use",
373 AddrNotAvailable => "address not available",
374 AlreadyExists => "entity already exists",
375 ArgumentListTooLong => "argument list too long",
376 BrokenPipe => "broken pipe",
377 ConnectionAborted => "connection aborted",
378 ConnectionRefused => "connection refused",
379 ConnectionReset => "connection reset",
380 CrossesDevices => "cross-device link or rename",
381 Deadlock => "deadlock",
382 DirectoryNotEmpty => "directory not empty",
383 ExecutableFileBusy => "executable file busy",
384 FileTooLarge => "file too large",
385 FilenameTooLong => "filename too long",
386 FilesystemLoop => "filesystem loop or indirection limit (e.g. symlink loop)",
387 FilesystemQuotaExceeded => "filesystem quota exceeded",
388 HostUnreachable => "host unreachable",
389 Interrupted => "operation interrupted",
390 InvalidData => "invalid data",
391 InvalidInput => "invalid input parameter",
392 IsADirectory => "is a directory",
393 NetworkDown => "network down",
394 NetworkUnreachable => "network unreachable",
395 NotADirectory => "not a directory",
396 NotConnected => "not connected",
397 NotFound => "entity not found",
398 NotSeekable => "seek on unseekable file",
399 Other => "other error",
400 OutOfMemory => "out of memory",
401 PermissionDenied => "permission denied",
402 ReadOnlyFilesystem => "read-only filesystem or storage medium",
403 ResourceBusy => "resource busy",
404 StaleNetworkFileHandle => "stale network file handle",
405 StorageFull => "no storage space",
406 TimedOut => "timed out",
407 TooManyLinks => "too many links",
408 Uncategorized => "uncategorized error",
409 UnexpectedEof => "unexpected end of file",
410 Unsupported => "unsupported",
411 WouldBlock => "operation would block",
412 WriteZero => "write zero",
417 #[stable(feature = "io_errorkind_display", since = "1.60.0")]
418 impl fmt::Display for ErrorKind {
419 /// Shows a human-readable description of the `ErrorKind`.
421 /// This is similar to `impl Display for Error`, but doesn't require first converting to Error.
425 /// use std::io::ErrorKind;
426 /// assert_eq!("entity not found", ErrorKind::NotFound.to_string());
428 fn fmt(&self, fmt: &mut fmt::Formatter<'_>) -> fmt::Result {
429 fmt.write_str(self.as_str())
433 /// Intended for use for errors not exposed to the user, where allocating onto
434 /// the heap (for normal construction via Error::new) is too costly.
435 #[stable(feature = "io_error_from_errorkind", since = "1.14.0")]
436 impl From<ErrorKind> for Error {
437 /// Converts an [`ErrorKind`] into an [`Error`].
439 /// This conversion creates a new error with a simple representation of error kind.
444 /// use std::io::{Error, ErrorKind};
446 /// let not_found = ErrorKind::NotFound;
447 /// let error = Error::from(not_found);
448 /// assert_eq!("entity not found", format!("{}", error));
451 fn from(kind: ErrorKind) -> Error {
452 Error { repr: Repr::new_simple(kind) }
457 /// Creates a new I/O error from a known kind of error as well as an
458 /// arbitrary error payload.
460 /// This function is used to generically create I/O errors which do not
461 /// originate from the OS itself. The `error` argument is an arbitrary
462 /// payload which will be contained in this [`Error`].
464 /// If no extra payload is required, use the `From` conversion from
470 /// use std::io::{Error, ErrorKind};
472 /// // errors can be created from strings
473 /// let custom_error = Error::new(ErrorKind::Other, "oh no!");
475 /// // errors can also be created from other errors
476 /// let custom_error2 = Error::new(ErrorKind::Interrupted, custom_error);
478 /// // creating an error without payload
479 /// let eof_error = Error::from(ErrorKind::UnexpectedEof);
481 #[stable(feature = "rust1", since = "1.0.0")]
482 pub fn new<E>(kind: ErrorKind, error: E) -> Error
484 E: Into<Box<dyn error::Error + Send + Sync>>,
486 Self::_new(kind, error.into())
489 /// Creates a new I/O error from an arbitrary error payload.
491 /// This function is used to generically create I/O errors which do not
492 /// originate from the OS itself. It is a shortcut for [`Error::new`]
493 /// with [`ErrorKind::Other`].
498 /// #![feature(io_error_other)]
500 /// use std::io::Error;
502 /// // errors can be created from strings
503 /// let custom_error = Error::other("oh no!");
505 /// // errors can also be created from other errors
506 /// let custom_error2 = Error::other(custom_error);
508 #[unstable(feature = "io_error_other", issue = "91946")]
509 pub fn other<E>(error: E) -> Error
511 E: Into<Box<dyn error::Error + Send + Sync>>,
513 Self::_new(ErrorKind::Other, error.into())
516 fn _new(kind: ErrorKind, error: Box<dyn error::Error + Send + Sync>) -> Error {
517 Error { repr: Repr::new_custom(Box::new(Custom { kind, error })) }
520 /// Creates a new I/O error from a known kind of error as well as a constant
523 /// This function does not allocate.
525 /// You should not use this directly, and instead use the `const_io_error!`
526 /// macro: `io::const_io_error!(ErrorKind::Something, "some_message")`.
528 /// This function should maybe change to `from_static_message<const MSG: &'static
529 /// str>(kind: ErrorKind)` in the future, when const generics allow that.
531 pub(crate) const fn from_static_message(msg: &'static SimpleMessage) -> Error {
532 Self { repr: Repr::new_simple_message(msg) }
535 /// Returns an error representing the last OS error which occurred.
537 /// This function reads the value of `errno` for the target platform (e.g.
538 /// `GetLastError` on Windows) and will return a corresponding instance of
539 /// [`Error`] for the error code.
541 /// This should be called immediately after a call to a platform function,
542 /// otherwise the state of the error value is indeterminate. In particular,
543 /// other standard library functions may call platform functions that may
544 /// (or may not) reset the error value even if they succeed.
549 /// use std::io::Error;
551 /// let os_error = Error::last_os_error();
552 /// println!("last OS error: {:?}", os_error);
554 #[stable(feature = "rust1", since = "1.0.0")]
557 pub fn last_os_error() -> Error {
558 Error::from_raw_os_error(sys::os::errno() as i32)
561 /// Creates a new instance of an [`Error`] from a particular OS error code.
568 /// # if cfg!(target_os = "linux") {
571 /// let error = io::Error::from_raw_os_error(22);
572 /// assert_eq!(error.kind(), io::ErrorKind::InvalidInput);
579 /// # if cfg!(windows) {
582 /// let error = io::Error::from_raw_os_error(10022);
583 /// assert_eq!(error.kind(), io::ErrorKind::InvalidInput);
586 #[stable(feature = "rust1", since = "1.0.0")]
589 pub fn from_raw_os_error(code: i32) -> Error {
590 Error { repr: Repr::new_os(code) }
593 /// Returns the OS error that this error represents (if any).
595 /// If this [`Error`] was constructed via [`last_os_error`] or
596 /// [`from_raw_os_error`], then this function will return [`Some`], otherwise
597 /// it will return [`None`].
599 /// [`last_os_error`]: Error::last_os_error
600 /// [`from_raw_os_error`]: Error::from_raw_os_error
605 /// use std::io::{Error, ErrorKind};
607 /// fn print_os_error(err: &Error) {
608 /// if let Some(raw_os_err) = err.raw_os_error() {
609 /// println!("raw OS error: {:?}", raw_os_err);
611 /// println!("Not an OS error");
616 /// // Will print "raw OS error: ...".
617 /// print_os_error(&Error::last_os_error());
618 /// // Will print "Not an OS error".
619 /// print_os_error(&Error::new(ErrorKind::Other, "oh no!"));
622 #[stable(feature = "rust1", since = "1.0.0")]
625 pub fn raw_os_error(&self) -> Option<i32> {
626 match self.repr.data() {
627 ErrorData::Os(i) => Some(i),
628 ErrorData::Custom(..) => None,
629 ErrorData::Simple(..) => None,
630 ErrorData::SimpleMessage(..) => None,
634 /// Returns a reference to the inner error wrapped by this error (if any).
636 /// If this [`Error`] was constructed via [`new`] then this function will
637 /// return [`Some`], otherwise it will return [`None`].
639 /// [`new`]: Error::new
644 /// use std::io::{Error, ErrorKind};
646 /// fn print_error(err: &Error) {
647 /// if let Some(inner_err) = err.get_ref() {
648 /// println!("Inner error: {:?}", inner_err);
650 /// println!("No inner error");
655 /// // Will print "No inner error".
656 /// print_error(&Error::last_os_error());
657 /// // Will print "Inner error: ...".
658 /// print_error(&Error::new(ErrorKind::Other, "oh no!"));
661 #[stable(feature = "io_error_inner", since = "1.3.0")]
664 pub fn get_ref(&self) -> Option<&(dyn error::Error + Send + Sync + 'static)> {
665 match self.repr.data() {
666 ErrorData::Os(..) => None,
667 ErrorData::Simple(..) => None,
668 ErrorData::SimpleMessage(..) => None,
669 ErrorData::Custom(c) => Some(&*c.error),
673 /// Returns a mutable reference to the inner error wrapped by this error
676 /// If this [`Error`] was constructed via [`new`] then this function will
677 /// return [`Some`], otherwise it will return [`None`].
679 /// [`new`]: Error::new
684 /// use std::io::{Error, ErrorKind};
685 /// use std::{error, fmt};
686 /// use std::fmt::Display;
694 /// fn new() -> MyError {
696 /// v: "oh no!".to_string()
700 /// fn change_message(&mut self, new_message: &str) {
701 /// self.v = new_message.to_string();
705 /// impl error::Error for MyError {}
707 /// impl Display for MyError {
708 /// fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
709 /// write!(f, "MyError: {}", &self.v)
713 /// fn change_error(mut err: Error) -> Error {
714 /// if let Some(inner_err) = err.get_mut() {
715 /// inner_err.downcast_mut::<MyError>().unwrap().change_message("I've been changed!");
720 /// fn print_error(err: &Error) {
721 /// if let Some(inner_err) = err.get_ref() {
722 /// println!("Inner error: {}", inner_err);
724 /// println!("No inner error");
729 /// // Will print "No inner error".
730 /// print_error(&change_error(Error::last_os_error()));
731 /// // Will print "Inner error: ...".
732 /// print_error(&change_error(Error::new(ErrorKind::Other, MyError::new())));
735 #[stable(feature = "io_error_inner", since = "1.3.0")]
738 pub fn get_mut(&mut self) -> Option<&mut (dyn error::Error + Send + Sync + 'static)> {
739 match self.repr.data_mut() {
740 ErrorData::Os(..) => None,
741 ErrorData::Simple(..) => None,
742 ErrorData::SimpleMessage(..) => None,
743 ErrorData::Custom(c) => Some(&mut *c.error),
747 /// Consumes the `Error`, returning its inner error (if any).
749 /// If this [`Error`] was constructed via [`new`] then this function will
750 /// return [`Some`], otherwise it will return [`None`].
752 /// [`new`]: Error::new
757 /// use std::io::{Error, ErrorKind};
759 /// fn print_error(err: Error) {
760 /// if let Some(inner_err) = err.into_inner() {
761 /// println!("Inner error: {}", inner_err);
763 /// println!("No inner error");
768 /// // Will print "No inner error".
769 /// print_error(Error::last_os_error());
770 /// // Will print "Inner error: ...".
771 /// print_error(Error::new(ErrorKind::Other, "oh no!"));
774 #[stable(feature = "io_error_inner", since = "1.3.0")]
775 #[must_use = "`self` will be dropped if the result is not used"]
777 pub fn into_inner(self) -> Option<Box<dyn error::Error + Send + Sync>> {
778 match self.repr.into_data() {
779 ErrorData::Os(..) => None,
780 ErrorData::Simple(..) => None,
781 ErrorData::SimpleMessage(..) => None,
782 ErrorData::Custom(c) => Some(c.error),
786 /// Returns the corresponding [`ErrorKind`] for this error.
791 /// use std::io::{Error, ErrorKind};
793 /// fn print_error(err: Error) {
794 /// println!("{:?}", err.kind());
798 /// // Will print "Uncategorized".
799 /// print_error(Error::last_os_error());
800 /// // Will print "AddrInUse".
801 /// print_error(Error::new(ErrorKind::AddrInUse, "oh no!"));
804 #[stable(feature = "rust1", since = "1.0.0")]
807 pub fn kind(&self) -> ErrorKind {
808 match self.repr.data() {
809 ErrorData::Os(code) => sys::decode_error_kind(code),
810 ErrorData::Custom(c) => c.kind,
811 ErrorData::Simple(kind) => kind,
812 ErrorData::SimpleMessage(m) => m.kind,
817 impl fmt::Debug for Repr {
818 fn fmt(&self, fmt: &mut fmt::Formatter<'_>) -> fmt::Result {
820 ErrorData::Os(code) => fmt
822 .field("code", &code)
823 .field("kind", &sys::decode_error_kind(code))
824 .field("message", &sys::os::error_string(code))
826 ErrorData::Custom(c) => fmt::Debug::fmt(&c, fmt),
827 ErrorData::Simple(kind) => fmt.debug_tuple("Kind").field(&kind).finish(),
828 ErrorData::SimpleMessage(msg) => fmt
829 .debug_struct("Error")
830 .field("kind", &msg.kind)
831 .field("message", &msg.message)
837 #[stable(feature = "rust1", since = "1.0.0")]
838 impl fmt::Display for Error {
839 fn fmt(&self, fmt: &mut fmt::Formatter<'_>) -> fmt::Result {
840 match self.repr.data() {
841 ErrorData::Os(code) => {
842 let detail = sys::os::error_string(code);
843 write!(fmt, "{} (os error {})", detail, code)
845 ErrorData::Custom(ref c) => c.error.fmt(fmt),
846 ErrorData::Simple(kind) => write!(fmt, "{}", kind.as_str()),
847 ErrorData::SimpleMessage(msg) => msg.message.fmt(fmt),
852 #[stable(feature = "rust1", since = "1.0.0")]
853 impl error::Error for Error {
854 #[allow(deprecated, deprecated_in_future)]
855 fn description(&self) -> &str {
856 match self.repr.data() {
857 ErrorData::Os(..) | ErrorData::Simple(..) => self.kind().as_str(),
858 ErrorData::SimpleMessage(msg) => msg.message,
859 ErrorData::Custom(c) => c.error.description(),
864 fn cause(&self) -> Option<&dyn error::Error> {
865 match self.repr.data() {
866 ErrorData::Os(..) => None,
867 ErrorData::Simple(..) => None,
868 ErrorData::SimpleMessage(..) => None,
869 ErrorData::Custom(c) => c.error.cause(),
873 fn source(&self) -> Option<&(dyn error::Error + 'static)> {
874 match self.repr.data() {
875 ErrorData::Os(..) => None,
876 ErrorData::Simple(..) => None,
877 ErrorData::SimpleMessage(..) => None,
878 ErrorData::Custom(c) => c.error.source(),
883 fn _assert_error_is_sync_send() {
884 fn _is_sync_send<T: Sync + Send>() {}
885 _is_sync_send::<Error>();