Foreign.C.Error

Different operating systems and/or C libraries often support different values of errno. This module defines the common values, but due to the open definition of Errno users may add definitions which are not predefined.

e2BIG :: Errno

Errno functions

isValidErrno :: Errno -> Bool

Yield True if the given Errno value is valid on the system. This implies that the Eq instance of Errno is also system dependent as it is only defined for valid values of Errno.

getErrno :: IO Errno

Get the current value of errno in the current thread.

resetErrno :: IO ()

Reset the current thread's errno value to eOK.

errnoToIOError

:: String	the location where the error occurred
-> Errno	the error number
-> Maybe Handle	optional handle associated with the error
-> Maybe String	optional filename associated with the error
-> IOError
Construct a Haskell 98 I/O error based on the given `Errno` value. The optional information can be used to improve the accuracy of error messages.

throwErrno

::
=> String	textual description of the error location
-> IO a
Throw an `IOError` corresponding to the current value of `getErrno`.

Guards for IO operations that may fail

throwErrnoIf

::
=> a -> Bool	predicate to apply to the result value of the `IO` operation
-> String	textual description of the location
-> IO a	the `IO` operation to be executed
-> IO a
Throw an `IOError` corresponding to the current value of `getErrno` if the result value of the `IO` action meets the given predicate.

throwErrnoIf_ :: (a -> Bool) -> String -> IO a -> IO ()

as throwErrnoIf, but discards the result of the IO action after error handling.

throwErrnoIfRetry :: (a -> Bool) -> String -> IO a -> IO a

as throwErrnoIf, but retry the IO action when it yields the error code eINTR - this amounts to the standard retry loop for interrupted POSIX system calls.

throwErrnoIfRetry_ :: (a -> Bool) -> String -> IO a -> IO ()

as throwErrnoIfRetry, but discards the result.

throwErrnoIfMinus1 :: Num a => String -> IO a -> IO a

Throw an IOError corresponding to the current value of getErrno if the IO action returns a result of -1.

throwErrnoIfMinus1_ :: Num a => String -> IO a -> IO ()

as throwErrnoIfMinus1, but discards the result.

throwErrnoIfMinus1Retry :: Num a => String -> IO a -> IO a

Throw an IOError corresponding to the current value of getErrno if the IO action returns a result of -1, but retries in case of an interrupted operation.

throwErrnoIfMinus1Retry_ :: Num a => String -> IO a -> IO ()

as throwErrnoIfMinus1, but discards the result.

throwErrnoIfNull :: String -> IO (Ptr a) -> IO (Ptr a)

Throw an IOError corresponding to the current value of getErrno if the IO action returns nullPtr.

throwErrnoIfNullRetry :: String -> IO (Ptr a) -> IO (Ptr a)

Throw an IOError corresponding to the current value of getErrno if the IO action returns nullPtr, but retry in case of an interrupted operation.

throwErrnoIfRetryMayBlock

::
=> a -> Bool	predicate to apply to the result value of the `IO` operation
-> String	textual description of the location
-> IO a	the `IO` operation to be executed
-> IO b	action to execute before retrying if an immediate retry would block
-> IO a
as `throwErrnoIfRetry`, but checks for operations that would block and executes an alternative action before retrying in that case.

throwErrnoIfRetryMayBlock_ :: (a -> Bool) -> String -> IO a -> IO b -> IO ()

as throwErrnoIfRetryMayBlock, but discards the result.

throwErrnoIfMinus1RetryMayBlock :: Num a => String -> IO a -> IO b -> IO a

as throwErrnoIfMinus1Retry, but checks for operations that would block.

throwErrnoIfMinus1RetryMayBlock_ :: Num a => String -> IO a -> IO b -> IO ()

as throwErrnoIfMinus1RetryMayBlock, but discards the result.

throwErrnoIfNullRetryMayBlock :: String -> IO (Ptr a) -> IO b -> IO (Ptr a)

as throwErrnoIfNullRetry, but checks for operations that would block.

throwErrnoPath :: String -> FilePath -> IO a

as throwErrno, but exceptions include the given path when appropriate.

throwErrnoPathIf :: (a -> Bool) -> String -> FilePath -> IO a -> IO a

as throwErrnoIf, but exceptions include the given path when appropriate.

throwErrnoPathIf_ :: (a -> Bool) -> String -> FilePath -> IO a -> IO ()

as throwErrnoIf_, but exceptions include the given path when appropriate.

throwErrnoPathIfNull :: String -> FilePath -> IO (Ptr a) -> IO (Ptr a)

as throwErrnoIfNull, but exceptions include the given path when appropriate.

throwErrnoPathIfMinus1 :: Num a => String -> FilePath -> IO a -> IO a

as throwErrnoIfMinus1, but exceptions include the given path when appropriate.

throwErrnoPathIfMinus1_ :: Num a => String -> FilePath -> IO a -> IO ()

as throwErrnoIfMinus1_, but exceptions include the given path when appropriate.

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