Portability	portable
Stability	provisional
Maintainer	ffi@haskell.org
Safe Haskell	Trustworthy

Foreign.C.Error

Contents

Haskell representations of errno values
- Common errno symbols
- Errno functions
- Guards for IO operations that may fail

Description

C-specific Marshalling support: Handling of C "errno" error codes.

Synopsis

Haskell representations of `errno` values

newtype Errno Source

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, eXDEV, eWOULDBLOCK, eUSERS, eTXTBSY, eTOOMANYREFS, eTIMEDOUT, eTIME, eSTALE, eSRMNT, eSRCH, eSPIPE, eSOCKTNOSUPPORT, eSHUTDOWN, eRREMOTE, eRPCMISMATCH, eROFS, eREMOTE, eREMCHG, eRANGE, ePROTOTYPE, ePROTONOSUPPORT, ePROTO, ePROGUNAVAIL, ePROGMISMATCH, ePROCUNAVAIL, ePROCLIM, ePIPE, ePFNOSUPPORT, ePERM, eOPNOTSUPP, eNXIO, eNOTTY, eNOTSOCK, eNOTEMPTY, eNOTDIR, eNOTCONN, eNOTBLK, eNOSYS, eNOSTR, eNOSR, eNOSPC, eNOPROTOOPT, eNONET, eNOMSG, eNOMEM, eNOLINK, eNOLCK, eNOEXEC, eNOENT, eNODEV, eNODATA, eNOBUFS, eNFILE, eNETUNREACH, eNETRESET, eNETDOWN, eNAMETOOLONG, eMULTIHOP, eMSGSIZE, eMLINK, eMFILE, eLOOP, eISDIR, eISCONN, eIO, eINVAL, eINTR, eINPROGRESS, eILSEQ, eIDRM, eHOSTUNREACH, eHOSTDOWN, eFTYPE, eFBIG, eFAULT, eEXIST, eDQUOT, eDOM, eDIRTY, eDESTADDRREQ, eDEADLK, eCONNRESET, eCONNREFUSED, eCONNABORTED, eCOMM, eCHILD, eBUSY, eBADRPC, eBADMSG, eBADF, eALREADY, eAGAIN, eAFNOSUPPORT, eADV, eADDRNOTAVAIL, eADDRINUSE, eACCES, e2BIG :: Errno Source

`Errno` functions

isValidErrno :: Errno -> Bool Source

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 Source

Get the current value of errno in the current thread.

resetErrno :: IO ()Source

Reset the current thread's errno value to eOK.

errnoToIOError Source

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 Source

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 Source

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 ()Source

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

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

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 ()Source

as throwErrnoIfRetry, but discards the result.

throwErrnoIfMinus1 :: (Eq a, Num a) => String -> IO a -> IO aSource

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 ()Source

as throwErrnoIfMinus1, but discards the result.

throwErrnoIfMinus1Retry :: (Eq a, Num a) => String -> IO a -> IO aSource

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 ()Source

as throwErrnoIfMinus1, but discards the result.

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

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

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

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 Source

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 ()Source

as throwErrnoIfRetryMayBlock, but discards the result.

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

as throwErrnoIfMinus1Retry, but checks for operations that would block.

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

as throwErrnoIfMinus1RetryMayBlock, but discards the result.

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

as throwErrnoIfNullRetry, but checks for operations that would block.

throwErrnoPath :: String -> FilePath -> IO aSource

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

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

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