#[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,
}
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
io_error_more
#86442)The remote host is not reachable.
NetworkUnreachable
io_error_more
#86442)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
io_error_more
#86442)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
io_error_more
#86442)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
io_error_more
#86442)The filesystem object is, unexpectedly, a directory.
A directory was specified when a non-directory was expected.
DirectoryNotEmpty
io_error_more
#86442)A non-empty directory was specified where an empty directory was expected.
ReadOnlyFilesystem
io_error_more
#86442)The filesystem or storage medium is read-only, but a write operation was attempted.
FilesystemLoop
io_error_more
#86442)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
io_error_more
#86442)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
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
io_error_more
#86442)The underlying storage (typically, a filesystem) is full.
This does not include out of quota errors.
NotSeekable
io_error_more
#86442)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
io_error_more
#86442)Filesystem quota was exceeded.
FileTooLarge
io_error_more
#86442)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
io_error_more
#86442)Resource is busy.
ExecutableFileBusy
io_error_more
#86442)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
io_error_more
#86442)Deadlock (avoided).
A file locking operation would result in deadlock. This situation is typically detected, if at all, on a best-effort basis.
CrossesDevices
io_error_more
#86442)Cross-device or cross-filesystem (hard) link or rename.
TooManyLinks
io_error_more
#86442)Too many (hard) links to the same filesystem object.
The filesystem does not support making so many hardlinks to the same file.
InvalidFilename
io_error_more
#86442)A filename was invalid.
This error can also cause if it exceeded the filename length limit.
ArgumentListTooLong
io_error_more
#86442)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
This operation is unsupported on this platform.
This means that the operation can never succeed.
UnexpectedEof
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
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 · source§impl 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.