#[non_exhaustive]
pub enum ErrorKind {
Show 40 variants
NotFound,
PermissionDenied,
ConnectionRefused,
ConnectionReset,
HostUnreachable,
NetworkUnreachable,
ConnectionAborted,
NotConnected,
AddrInUse,
AddrNotAvailable,
NetworkDown,
BrokenPipe,
AlreadyExists,
WouldBlock,
NotADirectory,
IsADirectory,
DirectoryNotEmpty,
ReadOnlyFilesystem,
FilesystemLoop,
StaleNetworkFileHandle,
InvalidInput,
InvalidData,
TimedOut,
WriteZero,
StorageFull,
NotSeekable,
FilesystemQuotaExceeded,
FileTooLarge,
ResourceBusy,
ExecutableFileBusy,
Deadlock,
CrossesDevices,
TooManyLinks,
InvalidFilename,
ArgumentListTooLong,
Interrupted,
Unsupported,
UnexpectedEof,
OutOfMemory,
Other,
// some variants omitted
}
Expand description
A list specifying general categories of I/O error.
This list is intended to grow over time and it is not recommended to exhaustively match against it.
It is used with the io::Error
type.
Handling errors and matching on ErrorKind
In application code, use match
for the ErrorKind
values you are
expecting; use _
to match “all other errors”.
In comprehensive and thorough tests that want to verify that a test doesn’t
return any known incorrect error kind, you may want to cut-and-paste the
current full list of errors from here into your test code, and then match
_
as the correct case. This seems counterintuitive, but it will make your
tests more robust. In particular, if you want to verify that your code does
produce an unrecognized error kind, the robust solution is to check for all
the recognized error kinds and fail in those cases.
Variants (Non-exhaustive)
This enum is marked as non-exhaustive
NotFound
An entity was not found, often a file.
PermissionDenied
The operation lacked the necessary privileges to complete.
ConnectionRefused
The connection was refused by the remote server.
ConnectionReset
The connection was reset by the remote server.
HostUnreachable
The remote host is not reachable.
NetworkUnreachable
The network containing the remote host is not reachable.
ConnectionAborted
The connection was aborted (terminated) by the remote server.
NotConnected
The network operation failed because it was not connected yet.
AddrInUse
A socket address could not be bound because the address is already in use elsewhere.
AddrNotAvailable
A nonexistent interface was requested or the requested address was not local.
NetworkDown
The system’s networking is down.
BrokenPipe
The operation failed because a pipe was closed.
AlreadyExists
An entity already exists, often a file.
WouldBlock
The operation needs to block to complete, but the blocking operation was requested to not occur.
NotADirectory
A filesystem object is, unexpectedly, not a directory.
For example, a filesystem path was specified where one of the intermediate directory components was, in fact, a plain file.
IsADirectory
The filesystem object is, unexpectedly, a directory.
A directory was specified when a non-directory was expected.
DirectoryNotEmpty
A non-empty directory was specified where an empty directory was expected.
ReadOnlyFilesystem
The filesystem or storage medium is read-only, but a write operation was attempted.
FilesystemLoop
Loop in the filesystem or IO subsystem; often, too many levels of symbolic links.
There was a loop (or excessively long chain) resolving a filesystem object or file IO object.
On Unix this is usually the result of a symbolic link loop; or, of exceeding the system-specific limit on the depth of symlink traversal.
StaleNetworkFileHandle
Stale network file handle.
With some network filesystems, notably NFS, an open file (or directory) can be invalidated by problems with the network or server.
InvalidInput
A parameter was incorrect.
InvalidData
1.2.0
Data not valid for the operation were encountered.
Unlike InvalidInput
, this typically means that the operation
parameters were valid, however the error was caused by malformed
input data.
For example, a function that reads a file into a string will error with
InvalidData
if the file’s contents are not valid UTF-8.
TimedOut
The I/O operation’s timeout expired, causing it to be canceled.
WriteZero
An error returned when an operation could not be completed because a
call to write
returned Ok(0)
.
This typically means that an operation could only succeed if it wrote a particular number of bytes but only a smaller number of bytes could be written.
StorageFull
The underlying storage (typically, a filesystem) is full.
This does not include out of quota errors.
NotSeekable
Seek on unseekable file.
Seeking was attempted on an open file handle which is not suitable for seeking - for
example, on Unix, a named pipe opened with File::open
.
FilesystemQuotaExceeded
Filesystem quota was exceeded.
FileTooLarge
File larger than allowed or supported.
This might arise from a hard limit of the underlying filesystem or file access API, or from an administratively imposed resource limitation. Simple disk full, and out of quota, have their own errors.
ResourceBusy
Resource is busy.
ExecutableFileBusy
Executable file is busy.
An attempt was made to write to a file which is also in use as a running program. (Not all operating systems detect this situation.)
Deadlock
Deadlock (avoided).
A file locking operation would result in deadlock. This situation is typically detected, if at all, on a best-effort basis.
CrossesDevices
Cross-device or cross-filesystem (hard) link or rename.
TooManyLinks
Too many (hard) links to the same filesystem object.
The filesystem does not support making so many hardlinks to the same file.
InvalidFilename
A filename was invalid.
This error can also cause if it exceeded the filename length limit.
ArgumentListTooLong
Program argument list too long.
When trying to run an external program, a system or process limit on the size of the arguments would have been exceeded.
Interrupted
This operation was interrupted.
Interrupted operations can typically be retried.
Unsupported
1.53.0
This operation is unsupported on this platform.
This means that the operation can never succeed.
UnexpectedEof
1.6.0
An error returned when an operation could not be completed because an “end of file” was reached prematurely.
This typically means that an operation could only succeed if it read a particular number of bytes but only a smaller number of bytes could be read.
OutOfMemory
1.54.0
An operation could not be completed, because it failed to allocate enough memory.
Other
A custom error that does not fall under any other I/O error kind.
This can be used to construct your own Error
s that do not match any
ErrorKind
.
This ErrorKind
is not used by the standard library.
Errors from the standard library that do not fall under any of the I/O
error kinds cannot be match
ed on, and will only match a wildcard (_
) pattern.
New ErrorKind
s might be added in the future for some of those.
Trait Implementations
1.14.0 · sourceimpl From<ErrorKind> for Error
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.
sourceimpl Ord for ErrorKind
impl Ord for ErrorKind
sourceimpl PartialOrd<ErrorKind> for ErrorKind
impl PartialOrd<ErrorKind> for ErrorKind
sourcefn partial_cmp(&self, other: &ErrorKind) -> Option<Ordering>
fn partial_cmp(&self, other: &ErrorKind) -> Option<Ordering>
This method returns an ordering between self
and other
values if one exists. Read more
sourcefn lt(&self, other: &Rhs) -> bool
fn lt(&self, other: &Rhs) -> bool
This method tests less than (for self
and other
) and is used by the <
operator. Read more
sourcefn le(&self, other: &Rhs) -> bool
fn le(&self, other: &Rhs) -> bool
This method tests less than or equal to (for self
and other
) and is used by the <=
operator. Read more
impl Copy for ErrorKind
impl Eq for ErrorKind
impl StructuralEq for ErrorKind
impl StructuralPartialEq for ErrorKind
Auto Trait Implementations
impl RefUnwindSafe for ErrorKind
impl Send for ErrorKind
impl Sync for ErrorKind
impl Unpin for ErrorKind
impl UnwindSafe for ErrorKind
Blanket Implementations
sourceimpl<T> BorrowMut<T> for T where
T: ?Sized,
impl<T> BorrowMut<T> for T where
T: ?Sized,
const: unstable · sourcefn borrow_mut(&mut self) -> &mut T
fn borrow_mut(&mut self) -> &mut T
Mutably borrows from an owned value. Read more
sourceimpl<T> ToOwned for T where
T: Clone,
impl<T> ToOwned for T where
T: Clone,
type Owned = T
type Owned = T
The resulting type after obtaining ownership.
sourcefn clone_into(&self, target: &mut T)
fn clone_into(&self, target: &mut T)
Uses borrowed data to replace owned data, usually by cloning. Read more