Safe Haskell	Safe
Language	Haskell2010

Foreign.C.Error

Contents

Haskell representations of errno values

Description

The module Foreign.C.Error facilitates C-specific error handling of errno.

Synopsis

Haskell representations of `errno` values

newtype Errno :: *

Haskell representation for errno values. The implementation is deliberately exposed, to allow users to add their own definitions of Errno values.

Constructors

Errno CInt

Instances

Eq Errno

Common `errno` symbols

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.

eOK :: Errno

e2BIG :: Errno

eACCES :: Errno

eADDRINUSE :: Errno

eADDRNOTAVAIL :: Errno

eADV :: Errno

eAFNOSUPPORT :: Errno

eAGAIN :: Errno

eALREADY :: Errno

eBADF :: Errno

eBADMSG :: Errno

eBADRPC :: Errno

eBUSY :: Errno

eCHILD :: Errno

eCOMM :: Errno

eCONNABORTED :: Errno

eCONNREFUSED :: Errno

eCONNRESET :: Errno

eDEADLK :: Errno

eDESTADDRREQ :: Errno

eDIRTY :: Errno

eDOM :: Errno

eDQUOT :: Errno

eEXIST :: Errno

eFAULT :: Errno

eFBIG :: Errno

eFTYPE :: Errno

eHOSTDOWN :: Errno

eHOSTUNREACH :: Errno

eIDRM :: Errno

eILSEQ :: Errno

eINPROGRESS :: Errno

eINTR :: Errno

eINVAL :: Errno

eIO :: Errno

eISCONN :: Errno

eISDIR :: Errno

eLOOP :: Errno

eMFILE :: Errno

eMLINK :: Errno

eMSGSIZE :: Errno

eMULTIHOP :: Errno

eNAMETOOLONG :: Errno

eNETDOWN :: Errno

eNETRESET :: Errno

eNETUNREACH :: Errno

eNFILE :: Errno

eNOBUFS :: Errno

eNODATA :: Errno

eNODEV :: Errno

eNOENT :: Errno

eNOEXEC :: Errno

eNOLCK :: Errno

eNOLINK :: Errno

eNOMEM :: Errno

eNOMSG :: Errno

eNONET :: Errno

eNOPROTOOPT :: Errno

eNOSPC :: Errno

eNOSR :: Errno

eNOSTR :: Errno

eNOSYS :: Errno

eNOTBLK :: Errno

eNOTCONN :: Errno

eNOTDIR :: Errno

eNOTEMPTY :: Errno

eNOTSOCK :: Errno

eNOTTY :: Errno

eNXIO :: Errno

eOPNOTSUPP :: Errno

ePERM :: Errno

ePFNOSUPPORT :: Errno

ePIPE :: Errno

ePROCLIM :: Errno

ePROCUNAVAIL :: Errno

ePROGMISMATCH :: Errno

ePROGUNAVAIL :: Errno

ePROTO :: Errno

ePROTONOSUPPORT :: Errno

ePROTOTYPE :: Errno

eRANGE :: Errno

eREMCHG :: Errno

eREMOTE :: Errno

eROFS :: Errno

eRPCMISMATCH :: Errno

eRREMOTE :: Errno

eSHUTDOWN :: Errno

eSOCKTNOSUPPORT :: Errno

eSPIPE :: Errno

eSRCH :: Errno

eSRMNT :: Errno

eSTALE :: Errno

eTIME :: Errno

eTIMEDOUT :: Errno

eTOOMANYREFS :: Errno

eTXTBSY :: Errno

eUSERS :: Errno

eWOULDBLOCK :: Errno

eXDEV :: 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

Arguments

:: 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 an IOError based on the given Errno value. The optional information can be used to improve the accuracy of error messages.

throwErrno

Arguments

:: 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

Arguments

:: (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 :: (Eq a, 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_ :: (Eq a, Num a) => String -> IO a -> IO ()

as throwErrnoIfMinus1, but discards the result.

throwErrnoIfMinus1Retry :: (Eq a, 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_ :: (Eq a, 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

Arguments

:: (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 additionally if the operation yields the error code eAGAIN or eWOULDBLOCK, an alternative action is executed before retrying.

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

as throwErrnoIfRetryMayBlock, but discards the result.

throwErrnoIfMinus1RetryMayBlock :: (Eq a, Num a) => String -> IO a -> IO b -> IO a

as throwErrnoIfMinus1Retry, but checks for operations that would block.

throwErrnoIfMinus1RetryMayBlock_ :: (Eq a, 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.