GHC.IOBase

IndexOutOfBounds String	An attempt was made to index an array outside its declared bounds.
UndefinedElement String	An attempt was made to evaluate an element of an array that had not been initialized.

Instances

Typeable ArrayException

Show ArrayException

data AsyncException

Asynchronous exceptions

Constructors

StackOverflow The current thread's stack exceeded its limit. Since an exception has been raised, the thread's stack will certainly be below its limit again, but the programmer should take remedial action immediately.

HeapOverflow

The program's heap is reaching its limit, and the program should take action to reduce the amount of live data it has. Notes:

It is undefined which thread receives this exception.
GHC currently does not throw HeapOverflow exceptions.

ThreadKilled This exception is raised by another thread calling killThread, or by the system if it needs to terminate the thread for some reason.

Instances

Typeable AsyncException

Show AsyncException

data Buffer

Constructors

Buffer

bufBuf :: RawBuffer
bufRPtr :: !Int
bufWPtr :: !Int
bufSize :: !Int
bufState :: BufferState

data BufferList

Constructors

BufferListNil
BufferListCons RawBuffer BufferList

data BufferMode

Constructors

NoBuffering
LineBuffering
BlockBuffering (Maybe Int)

data BufferState

Constructors

ReadBuffer
WriteBuffer

data Exception

The type of exceptions. Every kind of system-generated exception has a constructor in the Exception type, and values of other types may be injected into Exception by coercing them to Dynamic (see the section on Dynamic Exceptions).

For backwards compatibility with Haskell 98, IOError is a type synonym for Exception.

Constructors

ArithException ArithException	Exceptions raised by arithmetic operations. (NOTE: GHC currently does not throw `ArithException`s).
ArrayException ArrayException	Exceptions raised by array-related operations. (NOTE: GHC currently does not throw `ArrayException`s).
AssertionFailed String	This exception is thrown by the assert operation when the condition fails. The `String` argument contains the location of the assertion in the source program.
AsyncException AsyncException	Asynchronous exceptions (see section on Asynchronous Exceptions).
BlockedOnDeadMVar	The current thread was executing a call to takeMVar that could never return, because there are no other references to this `MVar`.
Deadlock	There are no runnable threads, so the program is deadlocked. The `Deadlock` exception is raised in the main thread only (see also: Control.Concurrent).
DynException Dynamic	Dynamically typed exceptions (see section on Dynamic Exceptions).
ErrorCall String	The `ErrorCall` exception is thrown by `error`. The `String` argument of `ErrorCall` is the string passed to `error` when it was called.
ExitException ExitCode	The `ExitException` exception is thrown by `exitWith` (and `exitFailure`). The `ExitCode` argument is the value passed to `exitWith`. An unhandled `ExitException` exception in the main thread will cause the program to be terminated with the given exit code.
IOException IOException	These are the standard IO exceptions generated by Haskell's `IO` operations. See also System.IO.Error.
NoMethodError String	An attempt was made to invoke a class method which has no definition in this instance, and there was no default definition given in the class declaration. GHC issues a warning when you compile an instance which has missing methods.
NonTermination	The current thread is stuck in an infinite loop. This exception may or may not be thrown when the program is non-terminating.
PatternMatchFail String	A pattern matching failure. The `String` argument should contain a descriptive message including the function name, source file and line number.
RecConError String	An attempt was made to evaluate a field of a record for which no value was given at construction time. The `String` argument gives the location of the record construction in the source program.
RecSelError String	A field selection was attempted on a constructor that doesn't have the requested field. This can happen with multi-constructor records when one or more fields are missing from some of the constructors. The `String` argument gives the location of the record selection in the source program.
RecUpdError String	An attempt was made to update a field in a record, where the record doesn't have the requested field. This can only occur with multi-constructor records, when one or more fields are missing from some of the constructors. The `String` argument gives the location of the record update in the source program.

Instances

Typeable Exception

Show Exception

Eq Exception

data ExitCode

Constructors

ExitSuccess
ExitFailure Int

type FD = Int

type FilePath = String

data Handle

Constructors

FileHandle !(MVar Handle__)
DuplexHandle !(MVar Handle__) !(MVar Handle__)

Instances

Typeable Handle

Eq Handle

Show Handle

data HandleType

Constructors

ClosedHandle
SemiClosedHandle
ReadHandle
WriteHandle
AppendHandle
ReadWriteHandle

Instances

Show HandleType

data Handle__

Constructors

Handle__

haFD :: !FD
haType :: HandleType
haIsBin :: Bool
haIsStream :: Bool
haBufferMode :: BufferMode
haFilePath :: FilePath
haBuffer :: !(IORef Buffer)
haBuffers :: !(IORef BufferList)
haOtherSide :: (Maybe (MVar Handle__))

newtype IO a

A value of type IO a is a computation which, when performed, does some I/O before returning a value of type a.

There is really only one way to "perform" an I/O action: bind it to Main.main in your program. When your program is run, the I/O will be performed. It isn't possible to perform I/O from an arbitrary function, unless that function is itself in the IO monad and called at some point, directly or indirectly, from Main.main.

IO is a monad, so IO actions can be combined using either the do-notation or the >> and >>= operations from the Monad class.

Constructors

IO (State# RealWorld -> (#State# RealWorld, a#))

Instances

MonadPlus IO

MonadError IOError IO

MonadFix IO

MonadIO IO

MArray IOArray e IO

MArray IOUArray Bool IO

MArray IOUArray Char IO

MArray IOUArray Int IO

MArray IOUArray Word IO

MArray IOUArray (Ptr a) IO

MArray IOUArray (FunPtr a) IO

MArray IOUArray Float IO

MArray IOUArray Double IO

MArray IOUArray (StablePtr a) IO

MArray IOUArray Int8 IO

MArray IOUArray Int16 IO

MArray IOUArray Int32 IO

MArray IOUArray Int64 IO

MArray IOUArray Word8 IO

MArray IOUArray Word16 IO

MArray IOUArray Word32 IO

MArray IOUArray Word64 IO

(Storable e) => MArray StorableArray e IO

(Typeable a) => Typeable (IO a)

Functor IO

Monad IO

type IOError = Exception

data IOErrorType

Constructors

AlreadyExists
NoSuchThing
ResourceBusy
ResourceExhausted
EOF
IllegalOperation
PermissionDenied
UserError
UnsatisfiedConstraints
SystemError
ProtocolError
OtherError
InvalidArgument
InappropriateType
HardwareFault
UnsupportedOperation
TimeExpired
ResourceVanished
Interrupted
DynIOError Dynamic

Instances

Eq IOErrorType

Show IOErrorType

data IOException

Constructors

IOError

ioe_handle :: (Maybe Handle)
ioe_type :: IOErrorType
ioe_location :: String
ioe_descr :: String
ioe_filename :: (Maybe FilePath)

Instances

Typeable IOException

Eq IOException

Show IOException

newtype IORef a

A mutable variable in the IO monad

Constructors

IORef (STRef RealWorld a)

Instances

(Typeable a) => Typeable (IORef a)

data MVar a

An MVar (pronounced "em-var") is a synchronising variable, used for communication between concurrent threads. It can be thought of as a a box, which may be empty or full.

Constructors

MVar (MVar# RealWorld a)

Instances

Eq (MVar a)

type RawBuffer = MutableByteArray# RealWorld

data IOErrorType

Constructors

AlreadyExists
NoSuchThing
ResourceBusy
ResourceExhausted
EOF
IllegalOperation
PermissionDenied
UserError
UnsatisfiedConstraints
SystemError
ProtocolError
OtherError
InvalidArgument
InappropriateType
HardwareFault
UnsupportedOperation
TimeExpired
ResourceVanished
Interrupted
DynIOError Dynamic

data HandleType

Constructors

ClosedHandle
SemiClosedHandle
ReadHandle
WriteHandle
AppendHandle
ReadWriteHandle

data Exception

For backwards compatibility with Haskell 98, IOError is a type synonym for Exception.

Constructors

ArithException ArithException	Exceptions raised by arithmetic operations. (NOTE: GHC currently does not throw `ArithException`s).
ArrayException ArrayException	Exceptions raised by array-related operations. (NOTE: GHC currently does not throw `ArrayException`s).
AssertionFailed String	This exception is thrown by the assert operation when the condition fails. The `String` argument contains the location of the assertion in the source program.
AsyncException AsyncException	Asynchronous exceptions (see section on Asynchronous Exceptions).
BlockedOnDeadMVar	The current thread was executing a call to takeMVar that could never return, because there are no other references to this `MVar`.
Deadlock	There are no runnable threads, so the program is deadlocked. The `Deadlock` exception is raised in the main thread only (see also: Control.Concurrent).
DynException Dynamic	Dynamically typed exceptions (see section on Dynamic Exceptions).
ErrorCall String	The `ErrorCall` exception is thrown by `error`. The `String` argument of `ErrorCall` is the string passed to `error` when it was called.
ExitException ExitCode	The `ExitException` exception is thrown by `exitWith` (and `exitFailure`). The `ExitCode` argument is the value passed to `exitWith`. An unhandled `ExitException` exception in the main thread will cause the program to be terminated with the given exit code.
IOException IOException	These are the standard IO exceptions generated by Haskell's `IO` operations. See also System.IO.Error.
NoMethodError String	An attempt was made to invoke a class method which has no definition in this instance, and there was no default definition given in the class declaration. GHC issues a warning when you compile an instance which has missing methods.
NonTermination	The current thread is stuck in an infinite loop. This exception may or may not be thrown when the program is non-terminating.
PatternMatchFail String	A pattern matching failure. The `String` argument should contain a descriptive message including the function name, source file and line number.
RecConError String	An attempt was made to evaluate a field of a record for which no value was given at construction time. The `String` argument gives the location of the record construction in the source program.
RecSelError String	A field selection was attempted on a constructor that doesn't have the requested field. This can happen with multi-constructor records when one or more fields are missing from some of the constructors. The `String` argument gives the location of the record selection in the source program.
RecUpdError String	An attempt was made to update a field in a record, where the record doesn't have the requested field. This can only occur with multi-constructor records, when one or more fields are missing from some of the constructors. The `String` argument gives the location of the record update in the source program.

data Exception

For backwards compatibility with Haskell 98, IOError is a type synonym for Exception.

Constructors

ArithException ArithException	Exceptions raised by arithmetic operations. (NOTE: GHC currently does not throw `ArithException`s).
ArrayException ArrayException	Exceptions raised by array-related operations. (NOTE: GHC currently does not throw `ArrayException`s).
AssertionFailed String	This exception is thrown by the assert operation when the condition fails. The `String` argument contains the location of the assertion in the source program.
AsyncException AsyncException	Asynchronous exceptions (see section on Asynchronous Exceptions).
BlockedOnDeadMVar	The current thread was executing a call to takeMVar that could never return, because there are no other references to this `MVar`.
Deadlock	There are no runnable threads, so the program is deadlocked. The `Deadlock` exception is raised in the main thread only (see also: Control.Concurrent).
DynException Dynamic	Dynamically typed exceptions (see section on Dynamic Exceptions).
ErrorCall String	The `ErrorCall` exception is thrown by `error`. The `String` argument of `ErrorCall` is the string passed to `error` when it was called.
ExitException ExitCode	The `ExitException` exception is thrown by `exitWith` (and `exitFailure`). The `ExitCode` argument is the value passed to `exitWith`. An unhandled `ExitException` exception in the main thread will cause the program to be terminated with the given exit code.
IOException IOException	These are the standard IO exceptions generated by Haskell's `IO` operations. See also System.IO.Error.
NoMethodError String	An attempt was made to invoke a class method which has no definition in this instance, and there was no default definition given in the class declaration. GHC issues a warning when you compile an instance which has missing methods.
NonTermination	The current thread is stuck in an infinite loop. This exception may or may not be thrown when the program is non-terminating.
PatternMatchFail String	A pattern matching failure. The `String` argument should contain a descriptive message including the function name, source file and line number.
RecConError String	An attempt was made to evaluate a field of a record for which no value was given at construction time. The `String` argument gives the location of the record construction in the source program.
RecSelError String	A field selection was attempted on a constructor that doesn't have the requested field. This can happen with multi-constructor records when one or more fields are missing from some of the constructors. The `String` argument gives the location of the record selection in the source program.
RecUpdError String	An attempt was made to update a field in a record, where the record doesn't have the requested field. This can only occur with multi-constructor records, when one or more fields are missing from some of the constructors. The `String` argument gives the location of the record update in the source program.

data Exception

For backwards compatibility with Haskell 98, IOError is a type synonym for Exception.

Constructors

ArithException ArithException	Exceptions raised by arithmetic operations. (NOTE: GHC currently does not throw `ArithException`s).
ArrayException ArrayException	Exceptions raised by array-related operations. (NOTE: GHC currently does not throw `ArrayException`s).
AssertionFailed String	This exception is thrown by the assert operation when the condition fails. The `String` argument contains the location of the assertion in the source program.
AsyncException AsyncException	Asynchronous exceptions (see section on Asynchronous Exceptions).
BlockedOnDeadMVar	The current thread was executing a call to takeMVar that could never return, because there are no other references to this `MVar`.
Deadlock	There are no runnable threads, so the program is deadlocked. The `Deadlock` exception is raised in the main thread only (see also: Control.Concurrent).
DynException Dynamic	Dynamically typed exceptions (see section on Dynamic Exceptions).
ErrorCall String	The `ErrorCall` exception is thrown by `error`. The `String` argument of `ErrorCall` is the string passed to `error` when it was called.
ExitException ExitCode	The `ExitException` exception is thrown by `exitWith` (and `exitFailure`). The `ExitCode` argument is the value passed to `exitWith`. An unhandled `ExitException` exception in the main thread will cause the program to be terminated with the given exit code.
IOException IOException	These are the standard IO exceptions generated by Haskell's `IO` operations. See also System.IO.Error.
NoMethodError String	An attempt was made to invoke a class method which has no definition in this instance, and there was no default definition given in the class declaration. GHC issues a warning when you compile an instance which has missing methods.
NonTermination	The current thread is stuck in an infinite loop. This exception may or may not be thrown when the program is non-terminating.
PatternMatchFail String	A pattern matching failure. The `String` argument should contain a descriptive message including the function name, source file and line number.
RecConError String	An attempt was made to evaluate a field of a record for which no value was given at construction time. The `String` argument gives the location of the record construction in the source program.
RecSelError String	A field selection was attempted on a constructor that doesn't have the requested field. This can happen with multi-constructor records when one or more fields are missing from some of the constructors. The `String` argument gives the location of the record selection in the source program.
RecUpdError String	An attempt was made to update a field in a record, where the record doesn't have the requested field. This can only occur with multi-constructor records, when one or more fields are missing from some of the constructors. The `String` argument gives the location of the record update in the source program.

data Exception

For backwards compatibility with Haskell 98, IOError is a type synonym for Exception.

Constructors

ArithException ArithException	Exceptions raised by arithmetic operations. (NOTE: GHC currently does not throw `ArithException`s).
ArrayException ArrayException	Exceptions raised by array-related operations. (NOTE: GHC currently does not throw `ArrayException`s).
AssertionFailed String	This exception is thrown by the assert operation when the condition fails. The `String` argument contains the location of the assertion in the source program.
AsyncException AsyncException	Asynchronous exceptions (see section on Asynchronous Exceptions).
BlockedOnDeadMVar	The current thread was executing a call to takeMVar that could never return, because there are no other references to this `MVar`.
Deadlock	There are no runnable threads, so the program is deadlocked. The `Deadlock` exception is raised in the main thread only (see also: Control.Concurrent).
DynException Dynamic	Dynamically typed exceptions (see section on Dynamic Exceptions).
ErrorCall String	The `ErrorCall` exception is thrown by `error`. The `String` argument of `ErrorCall` is the string passed to `error` when it was called.
ExitException ExitCode	The `ExitException` exception is thrown by `exitWith` (and `exitFailure`). The `ExitCode` argument is the value passed to `exitWith`. An unhandled `ExitException` exception in the main thread will cause the program to be terminated with the given exit code.
IOException IOException	These are the standard IO exceptions generated by Haskell's `IO` operations. See also System.IO.Error.
NoMethodError String	An attempt was made to invoke a class method which has no definition in this instance, and there was no default definition given in the class declaration. GHC issues a warning when you compile an instance which has missing methods.
NonTermination	The current thread is stuck in an infinite loop. This exception may or may not be thrown when the program is non-terminating.
PatternMatchFail String	A pattern matching failure. The `String` argument should contain a descriptive message including the function name, source file and line number.
RecConError String	An attempt was made to evaluate a field of a record for which no value was given at construction time. The `String` argument gives the location of the record construction in the source program.
RecSelError String	A field selection was attempted on a constructor that doesn't have the requested field. This can happen with multi-constructor records when one or more fields are missing from some of the constructors. The `String` argument gives the location of the record selection in the source program.
RecUpdError String	An attempt was made to update a field in a record, where the record doesn't have the requested field. This can only occur with multi-constructor records, when one or more fields are missing from some of the constructors. The `String` argument gives the location of the record update in the source program.

data BufferMode

Constructors

NoBuffering
LineBuffering
BlockBuffering (Maybe Int)

data Exception

For backwards compatibility with Haskell 98, IOError is a type synonym for Exception.

Constructors

ArithException ArithException	Exceptions raised by arithmetic operations. (NOTE: GHC currently does not throw `ArithException`s).
ArrayException ArrayException	Exceptions raised by array-related operations. (NOTE: GHC currently does not throw `ArrayException`s).
AssertionFailed String	This exception is thrown by the assert operation when the condition fails. The `String` argument contains the location of the assertion in the source program.
AsyncException AsyncException	Asynchronous exceptions (see section on Asynchronous Exceptions).
BlockedOnDeadMVar	The current thread was executing a call to takeMVar that could never return, because there are no other references to this `MVar`.
Deadlock	There are no runnable threads, so the program is deadlocked. The `Deadlock` exception is raised in the main thread only (see also: Control.Concurrent).
DynException Dynamic	Dynamically typed exceptions (see section on Dynamic Exceptions).
ErrorCall String	The `ErrorCall` exception is thrown by `error`. The `String` argument of `ErrorCall` is the string passed to `error` when it was called.
ExitException ExitCode	The `ExitException` exception is thrown by `exitWith` (and `exitFailure`). The `ExitCode` argument is the value passed to `exitWith`. An unhandled `ExitException` exception in the main thread will cause the program to be terminated with the given exit code.
IOException IOException	These are the standard IO exceptions generated by Haskell's `IO` operations. See also System.IO.Error.
NoMethodError String	An attempt was made to invoke a class method which has no definition in this instance, and there was no default definition given in the class declaration. GHC issues a warning when you compile an instance which has missing methods.
NonTermination	The current thread is stuck in an infinite loop. This exception may or may not be thrown when the program is non-terminating.
PatternMatchFail String	A pattern matching failure. The `String` argument should contain a descriptive message including the function name, source file and line number.
RecConError String	An attempt was made to evaluate a field of a record for which no value was given at construction time. The `String` argument gives the location of the record construction in the source program.
RecSelError String	A field selection was attempted on a constructor that doesn't have the requested field. This can happen with multi-constructor records when one or more fields are missing from some of the constructors. The `String` argument gives the location of the record selection in the source program.
RecUpdError String	An attempt was made to update a field in a record, where the record doesn't have the requested field. This can only occur with multi-constructor records, when one or more fields are missing from some of the constructors. The `String` argument gives the location of the record update in the source program.

data Buffer

Constructors

Buffer

bufBuf :: RawBuffer
bufRPtr :: !Int
bufWPtr :: !Int
bufSize :: !Int
bufState :: BufferState

data BufferList

Constructors

BufferListNil
BufferListCons RawBuffer BufferList

data BufferList

Constructors

BufferListNil
BufferListCons RawBuffer BufferList

data HandleType

Constructors

ClosedHandle
SemiClosedHandle
ReadHandle
WriteHandle
AppendHandle
ReadWriteHandle

data Exception

For backwards compatibility with Haskell 98, IOError is a type synonym for Exception.

Constructors

ArithException ArithException	Exceptions raised by arithmetic operations. (NOTE: GHC currently does not throw `ArithException`s).
ArrayException ArrayException	Exceptions raised by array-related operations. (NOTE: GHC currently does not throw `ArrayException`s).
AssertionFailed String	This exception is thrown by the assert operation when the condition fails. The `String` argument contains the location of the assertion in the source program.
AsyncException AsyncException	Asynchronous exceptions (see section on Asynchronous Exceptions).
BlockedOnDeadMVar	The current thread was executing a call to takeMVar that could never return, because there are no other references to this `MVar`.
Deadlock	There are no runnable threads, so the program is deadlocked. The `Deadlock` exception is raised in the main thread only (see also: Control.Concurrent).
DynException Dynamic	Dynamically typed exceptions (see section on Dynamic Exceptions).
ErrorCall String	The `ErrorCall` exception is thrown by `error`. The `String` argument of `ErrorCall` is the string passed to `error` when it was called.
ExitException ExitCode	The `ExitException` exception is thrown by `exitWith` (and `exitFailure`). The `ExitCode` argument is the value passed to `exitWith`. An unhandled `ExitException` exception in the main thread will cause the program to be terminated with the given exit code.
IOException IOException	These are the standard IO exceptions generated by Haskell's `IO` operations. See also System.IO.Error.
NoMethodError String	An attempt was made to invoke a class method which has no definition in this instance, and there was no default definition given in the class declaration. GHC issues a warning when you compile an instance which has missing methods.
NonTermination	The current thread is stuck in an infinite loop. This exception may or may not be thrown when the program is non-terminating.
PatternMatchFail String	A pattern matching failure. The `String` argument should contain a descriptive message including the function name, source file and line number.
RecConError String	An attempt was made to evaluate a field of a record for which no value was given at construction time. The `String` argument gives the location of the record construction in the source program.
RecSelError String	A field selection was attempted on a constructor that doesn't have the requested field. This can happen with multi-constructor records when one or more fields are missing from some of the constructors. The `String` argument gives the location of the record selection in the source program.
RecUpdError String	An attempt was made to update a field in a record, where the record doesn't have the requested field. This can only occur with multi-constructor records, when one or more fields are missing from some of the constructors. The `String` argument gives the location of the record update in the source program.

data ArithException

The type of arithmetic exceptions

Constructors

Overflow
Underflow
LossOfPrecision
DivideByZero
Denormal

data ArithException

The type of arithmetic exceptions

Constructors

Overflow
Underflow
LossOfPrecision
DivideByZero
Denormal

data Handle

Constructors

FileHandle !(MVar Handle__)
DuplexHandle !(MVar Handle__) !(MVar Handle__)

data Exception

For backwards compatibility with Haskell 98, IOError is a type synonym for Exception.

Constructors

ArithException ArithException	Exceptions raised by arithmetic operations. (NOTE: GHC currently does not throw `ArithException`s).
ArrayException ArrayException	Exceptions raised by array-related operations. (NOTE: GHC currently does not throw `ArrayException`s).
AssertionFailed String	This exception is thrown by the assert operation when the condition fails. The `String` argument contains the location of the assertion in the source program.
AsyncException AsyncException	Asynchronous exceptions (see section on Asynchronous Exceptions).
BlockedOnDeadMVar	The current thread was executing a call to takeMVar that could never return, because there are no other references to this `MVar`.
Deadlock	There are no runnable threads, so the program is deadlocked. The `Deadlock` exception is raised in the main thread only (see also: Control.Concurrent).
DynException Dynamic	Dynamically typed exceptions (see section on Dynamic Exceptions).
ErrorCall String	The `ErrorCall` exception is thrown by `error`. The `String` argument of `ErrorCall` is the string passed to `error` when it was called.
ExitException ExitCode	The `ExitException` exception is thrown by `exitWith` (and `exitFailure`). The `ExitCode` argument is the value passed to `exitWith`. An unhandled `ExitException` exception in the main thread will cause the program to be terminated with the given exit code.
IOException IOException	These are the standard IO exceptions generated by Haskell's `IO` operations. See also System.IO.Error.
NoMethodError String	An attempt was made to invoke a class method which has no definition in this instance, and there was no default definition given in the class declaration. GHC issues a warning when you compile an instance which has missing methods.
NonTermination	The current thread is stuck in an infinite loop. This exception may or may not be thrown when the program is non-terminating.
PatternMatchFail String	A pattern matching failure. The `String` argument should contain a descriptive message including the function name, source file and line number.
RecConError String	An attempt was made to evaluate a field of a record for which no value was given at construction time. The `String` argument gives the location of the record construction in the source program.
RecSelError String	A field selection was attempted on a constructor that doesn't have the requested field. This can happen with multi-constructor records when one or more fields are missing from some of the constructors. The `String` argument gives the location of the record selection in the source program.
RecUpdError String	An attempt was made to update a field in a record, where the record doesn't have the requested field. This can only occur with multi-constructor records, when one or more fields are missing from some of the constructors. The `String` argument gives the location of the record update in the source program.

data IOErrorType

Constructors

AlreadyExists
NoSuchThing
ResourceBusy
ResourceExhausted
EOF
IllegalOperation
PermissionDenied
UserError
UnsatisfiedConstraints
SystemError
ProtocolError
OtherError
InvalidArgument
InappropriateType
HardwareFault
UnsupportedOperation
TimeExpired
ResourceVanished
Interrupted
DynIOError Dynamic

data IOErrorType

Constructors

AlreadyExists
NoSuchThing
ResourceBusy
ResourceExhausted
EOF
IllegalOperation
PermissionDenied
UserError
UnsatisfiedConstraints
SystemError
ProtocolError
OtherError
InvalidArgument
InappropriateType
HardwareFault
UnsupportedOperation
TimeExpired
ResourceVanished
Interrupted
DynIOError Dynamic

data Exception

For backwards compatibility with Haskell 98, IOError is a type synonym for Exception.

Constructors

ArithException ArithException	Exceptions raised by arithmetic operations. (NOTE: GHC currently does not throw `ArithException`s).
ArrayException ArrayException	Exceptions raised by array-related operations. (NOTE: GHC currently does not throw `ArrayException`s).
AssertionFailed String	This exception is thrown by the assert operation when the condition fails. The `String` argument contains the location of the assertion in the source program.
AsyncException AsyncException	Asynchronous exceptions (see section on Asynchronous Exceptions).
BlockedOnDeadMVar	The current thread was executing a call to takeMVar that could never return, because there are no other references to this `MVar`.
Deadlock	There are no runnable threads, so the program is deadlocked. The `Deadlock` exception is raised in the main thread only (see also: Control.Concurrent).
DynException Dynamic	Dynamically typed exceptions (see section on Dynamic Exceptions).
ErrorCall String	The `ErrorCall` exception is thrown by `error`. The `String` argument of `ErrorCall` is the string passed to `error` when it was called.
ExitException ExitCode	The `ExitException` exception is thrown by `exitWith` (and `exitFailure`). The `ExitCode` argument is the value passed to `exitWith`. An unhandled `ExitException` exception in the main thread will cause the program to be terminated with the given exit code.
IOException IOException	These are the standard IO exceptions generated by Haskell's `IO` operations. See also System.IO.Error.
NoMethodError String	An attempt was made to invoke a class method which has no definition in this instance, and there was no default definition given in the class declaration. GHC issues a warning when you compile an instance which has missing methods.
NonTermination	The current thread is stuck in an infinite loop. This exception may or may not be thrown when the program is non-terminating.
PatternMatchFail String	A pattern matching failure. The `String` argument should contain a descriptive message including the function name, source file and line number.
RecConError String	An attempt was made to evaluate a field of a record for which no value was given at construction time. The `String` argument gives the location of the record construction in the source program.
RecSelError String	A field selection was attempted on a constructor that doesn't have the requested field. This can happen with multi-constructor records when one or more fields are missing from some of the constructors. The `String` argument gives the location of the record selection in the source program.
RecUpdError String	An attempt was made to update a field in a record, where the record doesn't have the requested field. This can only occur with multi-constructor records, when one or more fields are missing from some of the constructors. The `String` argument gives the location of the record update in the source program.

data Exception

For backwards compatibility with Haskell 98, IOError is a type synonym for Exception.

Constructors

ArithException ArithException	Exceptions raised by arithmetic operations. (NOTE: GHC currently does not throw `ArithException`s).
ArrayException ArrayException	Exceptions raised by array-related operations. (NOTE: GHC currently does not throw `ArrayException`s).
AssertionFailed String	This exception is thrown by the assert operation when the condition fails. The `String` argument contains the location of the assertion in the source program.
AsyncException AsyncException	Asynchronous exceptions (see section on Asynchronous Exceptions).
BlockedOnDeadMVar	The current thread was executing a call to takeMVar that could never return, because there are no other references to this `MVar`.
Deadlock	There are no runnable threads, so the program is deadlocked. The `Deadlock` exception is raised in the main thread only (see also: Control.Concurrent).
DynException Dynamic	Dynamically typed exceptions (see section on Dynamic Exceptions).
ErrorCall String	The `ErrorCall` exception is thrown by `error`. The `String` argument of `ErrorCall` is the string passed to `error` when it was called.
ExitException ExitCode	The `ExitException` exception is thrown by `exitWith` (and `exitFailure`). The `ExitCode` argument is the value passed to `exitWith`. An unhandled `ExitException` exception in the main thread will cause the program to be terminated with the given exit code.
IOException IOException	These are the standard IO exceptions generated by Haskell's `IO` operations. See also System.IO.Error.
NoMethodError String	An attempt was made to invoke a class method which has no definition in this instance, and there was no default definition given in the class declaration. GHC issues a warning when you compile an instance which has missing methods.
NonTermination	The current thread is stuck in an infinite loop. This exception may or may not be thrown when the program is non-terminating.
PatternMatchFail String	A pattern matching failure. The `String` argument should contain a descriptive message including the function name, source file and line number.
RecConError String	An attempt was made to evaluate a field of a record for which no value was given at construction time. The `String` argument gives the location of the record construction in the source program.
RecSelError String	A field selection was attempted on a constructor that doesn't have the requested field. This can happen with multi-constructor records when one or more fields are missing from some of the constructors. The `String` argument gives the location of the record selection in the source program.
RecUpdError String	An attempt was made to update a field in a record, where the record doesn't have the requested field. This can only occur with multi-constructor records, when one or more fields are missing from some of the constructors. The `String` argument gives the location of the record update in the source program.

data ExitCode

Constructors

ExitSuccess
ExitFailure Int

data ExitCode

Constructors

ExitSuccess
ExitFailure Int

data Handle

Constructors

FileHandle !(MVar Handle__)
DuplexHandle !(MVar Handle__) !(MVar Handle__)

data Handle__

Constructors

Handle__

haFD :: !FD
haType :: HandleType
haIsBin :: Bool
haIsStream :: Bool
haBufferMode :: BufferMode
haFilePath :: FilePath
haBuffer :: !(IORef Buffer)
haBuffers :: !(IORef BufferList)
haOtherSide :: (Maybe (MVar Handle__))

data IOErrorType

Constructors

AlreadyExists
NoSuchThing
ResourceBusy
ResourceExhausted
EOF
IllegalOperation
PermissionDenied
UserError
UnsatisfiedConstraints
SystemError
ProtocolError
OtherError
InvalidArgument
InappropriateType
HardwareFault
UnsupportedOperation
TimeExpired
ResourceVanished
Interrupted
DynIOError Dynamic

data AsyncException

Asynchronous exceptions

Constructors

HeapOverflow

The program's heap is reaching its limit, and the program should take action to reduce the amount of live data it has. Notes:

It is undefined which thread receives this exception.
GHC currently does not throw HeapOverflow exceptions.

ThreadKilled This exception is raised by another thread calling killThread, or by the system if it needs to terminate the thread for some reason.

newtype IO a

A value of type IO a is a computation which, when performed, does some I/O before returning a value of type a.

IO is a monad, so IO actions can be combined using either the do-notation or the >> and >>= operations from the Monad class.

Constructors

IO (State# RealWorld -> (#State# RealWorld, a#))

data IOException

Constructors

IOError

ioe_handle :: (Maybe Handle)
ioe_type :: IOErrorType
ioe_location :: String
ioe_descr :: String
ioe_filename :: (Maybe FilePath)

data Exception

For backwards compatibility with Haskell 98, IOError is a type synonym for Exception.

Constructors

ArithException ArithException	Exceptions raised by arithmetic operations. (NOTE: GHC currently does not throw `ArithException`s).
ArrayException ArrayException	Exceptions raised by array-related operations. (NOTE: GHC currently does not throw `ArrayException`s).
AssertionFailed String	This exception is thrown by the assert operation when the condition fails. The `String` argument contains the location of the assertion in the source program.
AsyncException AsyncException	Asynchronous exceptions (see section on Asynchronous Exceptions).
BlockedOnDeadMVar	The current thread was executing a call to takeMVar that could never return, because there are no other references to this `MVar`.
Deadlock	There are no runnable threads, so the program is deadlocked. The `Deadlock` exception is raised in the main thread only (see also: Control.Concurrent).
DynException Dynamic	Dynamically typed exceptions (see section on Dynamic Exceptions).
ErrorCall String	The `ErrorCall` exception is thrown by `error`. The `String` argument of `ErrorCall` is the string passed to `error` when it was called.
ExitException ExitCode	The `ExitException` exception is thrown by `exitWith` (and `exitFailure`). The `ExitCode` argument is the value passed to `exitWith`. An unhandled `ExitException` exception in the main thread will cause the program to be terminated with the given exit code.
IOException IOException	These are the standard IO exceptions generated by Haskell's `IO` operations. See also System.IO.Error.
NoMethodError String	An attempt was made to invoke a class method which has no definition in this instance, and there was no default definition given in the class declaration. GHC issues a warning when you compile an instance which has missing methods.
NonTermination	The current thread is stuck in an infinite loop. This exception may or may not be thrown when the program is non-terminating.
PatternMatchFail String	A pattern matching failure. The `String` argument should contain a descriptive message including the function name, source file and line number.
RecConError String	An attempt was made to evaluate a field of a record for which no value was given at construction time. The `String` argument gives the location of the record construction in the source program.
RecSelError String	A field selection was attempted on a constructor that doesn't have the requested field. This can happen with multi-constructor records when one or more fields are missing from some of the constructors. The `String` argument gives the location of the record selection in the source program.
RecUpdError String	An attempt was made to update a field in a record, where the record doesn't have the requested field. This can only occur with multi-constructor records, when one or more fields are missing from some of the constructors. The `String` argument gives the location of the record update in the source program.

newtype IORef a

A mutable variable in the IO monad

Constructors

IORef (STRef RealWorld a)

data IOErrorType

Constructors

AlreadyExists
NoSuchThing
ResourceBusy
ResourceExhausted
EOF
IllegalOperation
PermissionDenied
UserError
UnsatisfiedConstraints
SystemError
ProtocolError
OtherError
InvalidArgument
InappropriateType
HardwareFault
UnsupportedOperation
TimeExpired
ResourceVanished
Interrupted
DynIOError Dynamic

data IOErrorType

Constructors

AlreadyExists
NoSuchThing
ResourceBusy
ResourceExhausted
EOF
IllegalOperation
PermissionDenied
UserError
UnsatisfiedConstraints
SystemError
ProtocolError
OtherError
InvalidArgument
InappropriateType
HardwareFault
UnsupportedOperation
TimeExpired
ResourceVanished
Interrupted
DynIOError Dynamic

data ArrayException

Exceptions generated by array operations

Constructors

IndexOutOfBounds String	An attempt was made to index an array outside its declared bounds.
UndefinedElement String	An attempt was made to evaluate an element of an array that had not been initialized.

data IOErrorType

Constructors

AlreadyExists
NoSuchThing
ResourceBusy
ResourceExhausted
EOF
IllegalOperation
PermissionDenied
UserError
UnsatisfiedConstraints
SystemError
ProtocolError
OtherError
InvalidArgument
InappropriateType
HardwareFault
UnsupportedOperation
TimeExpired
ResourceVanished
Interrupted
DynIOError Dynamic

data IOErrorType

Constructors

AlreadyExists
NoSuchThing
ResourceBusy
ResourceExhausted
EOF
IllegalOperation
PermissionDenied
UserError
UnsatisfiedConstraints
SystemError
ProtocolError
OtherError
InvalidArgument
InappropriateType
HardwareFault
UnsupportedOperation
TimeExpired
ResourceVanished
Interrupted
DynIOError Dynamic

data BufferMode

Constructors

NoBuffering
LineBuffering
BlockBuffering (Maybe Int)

data ArithException

The type of arithmetic exceptions

Constructors

Overflow
Underflow
LossOfPrecision
DivideByZero
Denormal

data MVar a

An MVar (pronounced "em-var") is a synchronising variable, used for communication between concurrent threads. It can be thought of as a a box, which may be empty or full.

Constructors

MVar (MVar# RealWorld a)

data BufferMode

Constructors

NoBuffering
LineBuffering
BlockBuffering (Maybe Int)

data Exception

For backwards compatibility with Haskell 98, IOError is a type synonym for Exception.

Constructors

ArithException ArithException	Exceptions raised by arithmetic operations. (NOTE: GHC currently does not throw `ArithException`s).
ArrayException ArrayException	Exceptions raised by array-related operations. (NOTE: GHC currently does not throw `ArrayException`s).
AssertionFailed String	This exception is thrown by the assert operation when the condition fails. The `String` argument contains the location of the assertion in the source program.
AsyncException AsyncException	Asynchronous exceptions (see section on Asynchronous Exceptions).
BlockedOnDeadMVar	The current thread was executing a call to takeMVar that could never return, because there are no other references to this `MVar`.
Deadlock	There are no runnable threads, so the program is deadlocked. The `Deadlock` exception is raised in the main thread only (see also: Control.Concurrent).
DynException Dynamic	Dynamically typed exceptions (see section on Dynamic Exceptions).
ErrorCall String	The `ErrorCall` exception is thrown by `error`. The `String` argument of `ErrorCall` is the string passed to `error` when it was called.
ExitException ExitCode	The `ExitException` exception is thrown by `exitWith` (and `exitFailure`). The `ExitCode` argument is the value passed to `exitWith`. An unhandled `ExitException` exception in the main thread will cause the program to be terminated with the given exit code.
IOException IOException	These are the standard IO exceptions generated by Haskell's `IO` operations. See also System.IO.Error.
NoMethodError String	An attempt was made to invoke a class method which has no definition in this instance, and there was no default definition given in the class declaration. GHC issues a warning when you compile an instance which has missing methods.
NonTermination	The current thread is stuck in an infinite loop. This exception may or may not be thrown when the program is non-terminating.
PatternMatchFail String	A pattern matching failure. The `String` argument should contain a descriptive message including the function name, source file and line number.
RecConError String	An attempt was made to evaluate a field of a record for which no value was given at construction time. The `String` argument gives the location of the record construction in the source program.
RecSelError String	A field selection was attempted on a constructor that doesn't have the requested field. This can happen with multi-constructor records when one or more fields are missing from some of the constructors. The `String` argument gives the location of the record selection in the source program.
RecUpdError String	An attempt was made to update a field in a record, where the record doesn't have the requested field. This can only occur with multi-constructor records, when one or more fields are missing from some of the constructors. The `String` argument gives the location of the record update in the source program.

data IOErrorType

Constructors

AlreadyExists
NoSuchThing
ResourceBusy
ResourceExhausted
EOF
IllegalOperation
PermissionDenied
UserError
UnsatisfiedConstraints
SystemError
ProtocolError
OtherError
InvalidArgument
InappropriateType
HardwareFault
UnsupportedOperation
TimeExpired
ResourceVanished
Interrupted
DynIOError Dynamic

data Exception

For backwards compatibility with Haskell 98, IOError is a type synonym for Exception.

Constructors

ArithException ArithException	Exceptions raised by arithmetic operations. (NOTE: GHC currently does not throw `ArithException`s).
ArrayException ArrayException	Exceptions raised by array-related operations. (NOTE: GHC currently does not throw `ArrayException`s).
AssertionFailed String	This exception is thrown by the assert operation when the condition fails. The `String` argument contains the location of the assertion in the source program.
AsyncException AsyncException	Asynchronous exceptions (see section on Asynchronous Exceptions).
BlockedOnDeadMVar	The current thread was executing a call to takeMVar that could never return, because there are no other references to this `MVar`.
Deadlock	There are no runnable threads, so the program is deadlocked. The `Deadlock` exception is raised in the main thread only (see also: Control.Concurrent).
DynException Dynamic	Dynamically typed exceptions (see section on Dynamic Exceptions).
ErrorCall String	The `ErrorCall` exception is thrown by `error`. The `String` argument of `ErrorCall` is the string passed to `error` when it was called.
ExitException ExitCode	The `ExitException` exception is thrown by `exitWith` (and `exitFailure`). The `ExitCode` argument is the value passed to `exitWith`. An unhandled `ExitException` exception in the main thread will cause the program to be terminated with the given exit code.
IOException IOException	These are the standard IO exceptions generated by Haskell's `IO` operations. See also System.IO.Error.
NoMethodError String	An attempt was made to invoke a class method which has no definition in this instance, and there was no default definition given in the class declaration. GHC issues a warning when you compile an instance which has missing methods.
NonTermination	The current thread is stuck in an infinite loop. This exception may or may not be thrown when the program is non-terminating.
PatternMatchFail String	A pattern matching failure. The `String` argument should contain a descriptive message including the function name, source file and line number.
RecConError String	An attempt was made to evaluate a field of a record for which no value was given at construction time. The `String` argument gives the location of the record construction in the source program.
RecSelError String	A field selection was attempted on a constructor that doesn't have the requested field. This can happen with multi-constructor records when one or more fields are missing from some of the constructors. The `String` argument gives the location of the record selection in the source program.
RecUpdError String	An attempt was made to update a field in a record, where the record doesn't have the requested field. This can only occur with multi-constructor records, when one or more fields are missing from some of the constructors. The `String` argument gives the location of the record update in the source program.

data IOErrorType

Constructors

AlreadyExists
NoSuchThing
ResourceBusy
ResourceExhausted
EOF
IllegalOperation
PermissionDenied
UserError
UnsatisfiedConstraints
SystemError
ProtocolError
OtherError
InvalidArgument
InappropriateType
HardwareFault
UnsupportedOperation
TimeExpired
ResourceVanished
Interrupted
DynIOError Dynamic

data ArithException

The type of arithmetic exceptions

Constructors

Overflow
Underflow
LossOfPrecision
DivideByZero
Denormal

data Exception

For backwards compatibility with Haskell 98, IOError is a type synonym for Exception.

Constructors

ArithException ArithException	Exceptions raised by arithmetic operations. (NOTE: GHC currently does not throw `ArithException`s).
ArrayException ArrayException	Exceptions raised by array-related operations. (NOTE: GHC currently does not throw `ArrayException`s).
AssertionFailed String	This exception is thrown by the assert operation when the condition fails. The `String` argument contains the location of the assertion in the source program.
AsyncException AsyncException	Asynchronous exceptions (see section on Asynchronous Exceptions).
BlockedOnDeadMVar	The current thread was executing a call to takeMVar that could never return, because there are no other references to this `MVar`.
Deadlock	There are no runnable threads, so the program is deadlocked. The `Deadlock` exception is raised in the main thread only (see also: Control.Concurrent).
DynException Dynamic	Dynamically typed exceptions (see section on Dynamic Exceptions).
ErrorCall String	The `ErrorCall` exception is thrown by `error`. The `String` argument of `ErrorCall` is the string passed to `error` when it was called.
ExitException ExitCode	The `ExitException` exception is thrown by `exitWith` (and `exitFailure`). The `ExitCode` argument is the value passed to `exitWith`. An unhandled `ExitException` exception in the main thread will cause the program to be terminated with the given exit code.
IOException IOException	These are the standard IO exceptions generated by Haskell's `IO` operations. See also System.IO.Error.
NoMethodError String	An attempt was made to invoke a class method which has no definition in this instance, and there was no default definition given in the class declaration. GHC issues a warning when you compile an instance which has missing methods.
NonTermination	The current thread is stuck in an infinite loop. This exception may or may not be thrown when the program is non-terminating.
PatternMatchFail String	A pattern matching failure. The `String` argument should contain a descriptive message including the function name, source file and line number.
RecConError String	An attempt was made to evaluate a field of a record for which no value was given at construction time. The `String` argument gives the location of the record construction in the source program.
RecSelError String	A field selection was attempted on a constructor that doesn't have the requested field. This can happen with multi-constructor records when one or more fields are missing from some of the constructors. The `String` argument gives the location of the record selection in the source program.
RecUpdError String	An attempt was made to update a field in a record, where the record doesn't have the requested field. This can only occur with multi-constructor records, when one or more fields are missing from some of the constructors. The `String` argument gives the location of the record update in the source program.

data IOErrorType

Constructors

AlreadyExists
NoSuchThing
ResourceBusy
ResourceExhausted
EOF
IllegalOperation
PermissionDenied
UserError
UnsatisfiedConstraints
SystemError
ProtocolError
OtherError
InvalidArgument
InappropriateType
HardwareFault
UnsupportedOperation
TimeExpired
ResourceVanished
Interrupted
DynIOError Dynamic

data IOErrorType

Constructors

AlreadyExists
NoSuchThing
ResourceBusy
ResourceExhausted
EOF
IllegalOperation
PermissionDenied
UserError
UnsatisfiedConstraints
SystemError
ProtocolError
OtherError
InvalidArgument
InappropriateType
HardwareFault
UnsupportedOperation
TimeExpired
ResourceVanished
Interrupted
DynIOError Dynamic

data BufferState

Constructors

ReadBuffer
WriteBuffer

data HandleType

Constructors

ClosedHandle
SemiClosedHandle
ReadHandle
WriteHandle
AppendHandle
ReadWriteHandle

data HandleType

Constructors

ClosedHandle
SemiClosedHandle
ReadHandle
WriteHandle
AppendHandle
ReadWriteHandle

data Exception

For backwards compatibility with Haskell 98, IOError is a type synonym for Exception.

Constructors

ArithException ArithException	Exceptions raised by arithmetic operations. (NOTE: GHC currently does not throw `ArithException`s).
ArrayException ArrayException	Exceptions raised by array-related operations. (NOTE: GHC currently does not throw `ArrayException`s).
AssertionFailed String	This exception is thrown by the assert operation when the condition fails. The `String` argument contains the location of the assertion in the source program.
AsyncException AsyncException	Asynchronous exceptions (see section on Asynchronous Exceptions).
BlockedOnDeadMVar	The current thread was executing a call to takeMVar that could never return, because there are no other references to this `MVar`.
Deadlock	There are no runnable threads, so the program is deadlocked. The `Deadlock` exception is raised in the main thread only (see also: Control.Concurrent).
DynException Dynamic	Dynamically typed exceptions (see section on Dynamic Exceptions).
ErrorCall String	The `ErrorCall` exception is thrown by `error`. The `String` argument of `ErrorCall` is the string passed to `error` when it was called.
ExitException ExitCode	The `ExitException` exception is thrown by `exitWith` (and `exitFailure`). The `ExitCode` argument is the value passed to `exitWith`. An unhandled `ExitException` exception in the main thread will cause the program to be terminated with the given exit code.
IOException IOException	These are the standard IO exceptions generated by Haskell's `IO` operations. See also System.IO.Error.
NoMethodError String	An attempt was made to invoke a class method which has no definition in this instance, and there was no default definition given in the class declaration. GHC issues a warning when you compile an instance which has missing methods.
NonTermination	The current thread is stuck in an infinite loop. This exception may or may not be thrown when the program is non-terminating.
PatternMatchFail String	A pattern matching failure. The `String` argument should contain a descriptive message including the function name, source file and line number.
RecConError String	An attempt was made to evaluate a field of a record for which no value was given at construction time. The `String` argument gives the location of the record construction in the source program.
RecSelError String	A field selection was attempted on a constructor that doesn't have the requested field. This can happen with multi-constructor records when one or more fields are missing from some of the constructors. The `String` argument gives the location of the record selection in the source program.
RecUpdError String	An attempt was made to update a field in a record, where the record doesn't have the requested field. This can only occur with multi-constructor records, when one or more fields are missing from some of the constructors. The `String` argument gives the location of the record update in the source program.

data Exception

For backwards compatibility with Haskell 98, IOError is a type synonym for Exception.

Constructors

ArithException ArithException	Exceptions raised by arithmetic operations. (NOTE: GHC currently does not throw `ArithException`s).
ArrayException ArrayException	Exceptions raised by array-related operations. (NOTE: GHC currently does not throw `ArrayException`s).
AssertionFailed String	This exception is thrown by the assert operation when the condition fails. The `String` argument contains the location of the assertion in the source program.
AsyncException AsyncException	Asynchronous exceptions (see section on Asynchronous Exceptions).
BlockedOnDeadMVar	The current thread was executing a call to takeMVar that could never return, because there are no other references to this `MVar`.
Deadlock	There are no runnable threads, so the program is deadlocked. The `Deadlock` exception is raised in the main thread only (see also: Control.Concurrent).
DynException Dynamic	Dynamically typed exceptions (see section on Dynamic Exceptions).
ErrorCall String	The `ErrorCall` exception is thrown by `error`. The `String` argument of `ErrorCall` is the string passed to `error` when it was called.
ExitException ExitCode	The `ExitException` exception is thrown by `exitWith` (and `exitFailure`). The `ExitCode` argument is the value passed to `exitWith`. An unhandled `ExitException` exception in the main thread will cause the program to be terminated with the given exit code.
IOException IOException	These are the standard IO exceptions generated by Haskell's `IO` operations. See also System.IO.Error.
NoMethodError String	An attempt was made to invoke a class method which has no definition in this instance, and there was no default definition given in the class declaration. GHC issues a warning when you compile an instance which has missing methods.
NonTermination	The current thread is stuck in an infinite loop. This exception may or may not be thrown when the program is non-terminating.
PatternMatchFail String	A pattern matching failure. The `String` argument should contain a descriptive message including the function name, source file and line number.
RecConError String	An attempt was made to evaluate a field of a record for which no value was given at construction time. The `String` argument gives the location of the record construction in the source program.
RecSelError String	A field selection was attempted on a constructor that doesn't have the requested field. This can happen with multi-constructor records when one or more fields are missing from some of the constructors. The `String` argument gives the location of the record selection in the source program.
RecUpdError String	An attempt was made to update a field in a record, where the record doesn't have the requested field. This can only occur with multi-constructor records, when one or more fields are missing from some of the constructors. The `String` argument gives the location of the record update in the source program.

data Exception

For backwards compatibility with Haskell 98, IOError is a type synonym for Exception.

Constructors

ArithException ArithException	Exceptions raised by arithmetic operations. (NOTE: GHC currently does not throw `ArithException`s).
ArrayException ArrayException	Exceptions raised by array-related operations. (NOTE: GHC currently does not throw `ArrayException`s).
AssertionFailed String	This exception is thrown by the assert operation when the condition fails. The `String` argument contains the location of the assertion in the source program.
AsyncException AsyncException	Asynchronous exceptions (see section on Asynchronous Exceptions).
BlockedOnDeadMVar	The current thread was executing a call to takeMVar that could never return, because there are no other references to this `MVar`.
Deadlock	There are no runnable threads, so the program is deadlocked. The `Deadlock` exception is raised in the main thread only (see also: Control.Concurrent).
DynException Dynamic	Dynamically typed exceptions (see section on Dynamic Exceptions).
ErrorCall String	The `ErrorCall` exception is thrown by `error`. The `String` argument of `ErrorCall` is the string passed to `error` when it was called.
ExitException ExitCode	The `ExitException` exception is thrown by `exitWith` (and `exitFailure`). The `ExitCode` argument is the value passed to `exitWith`. An unhandled `ExitException` exception in the main thread will cause the program to be terminated with the given exit code.
IOException IOException	These are the standard IO exceptions generated by Haskell's `IO` operations. See also System.IO.Error.
NoMethodError String	An attempt was made to invoke a class method which has no definition in this instance, and there was no default definition given in the class declaration. GHC issues a warning when you compile an instance which has missing methods.
NonTermination	The current thread is stuck in an infinite loop. This exception may or may not be thrown when the program is non-terminating.
PatternMatchFail String	A pattern matching failure. The `String` argument should contain a descriptive message including the function name, source file and line number.
RecConError String	An attempt was made to evaluate a field of a record for which no value was given at construction time. The `String` argument gives the location of the record construction in the source program.
RecSelError String	A field selection was attempted on a constructor that doesn't have the requested field. This can happen with multi-constructor records when one or more fields are missing from some of the constructors. The `String` argument gives the location of the record selection in the source program.
RecUpdError String	An attempt was made to update a field in a record, where the record doesn't have the requested field. This can only occur with multi-constructor records, when one or more fields are missing from some of the constructors. The `String` argument gives the location of the record update in the source program.

data IOErrorType

Constructors

AlreadyExists
NoSuchThing
ResourceBusy
ResourceExhausted
EOF
IllegalOperation
PermissionDenied
UserError
UnsatisfiedConstraints
SystemError
ProtocolError
OtherError
InvalidArgument
InappropriateType
HardwareFault
UnsupportedOperation
TimeExpired
ResourceVanished
Interrupted
DynIOError Dynamic

data IOErrorType

Constructors

AlreadyExists
NoSuchThing
ResourceBusy
ResourceExhausted
EOF
IllegalOperation
PermissionDenied
UserError
UnsatisfiedConstraints
SystemError
ProtocolError
OtherError
InvalidArgument
InappropriateType
HardwareFault
UnsupportedOperation
TimeExpired
ResourceVanished
Interrupted
DynIOError Dynamic

data IOErrorType

Constructors

AlreadyExists
NoSuchThing
ResourceBusy
ResourceExhausted
EOF
IllegalOperation
PermissionDenied
UserError
UnsatisfiedConstraints
SystemError
ProtocolError
OtherError
InvalidArgument
InappropriateType
HardwareFault
UnsupportedOperation
TimeExpired
ResourceVanished
Interrupted
DynIOError Dynamic

data HandleType

Constructors

ClosedHandle
SemiClosedHandle
ReadHandle
WriteHandle
AppendHandle
ReadWriteHandle

data AsyncException

Asynchronous exceptions

Constructors

HeapOverflow

The program's heap is reaching its limit, and the program should take action to reduce the amount of live data it has. Notes:

It is undefined which thread receives this exception.
GHC currently does not throw HeapOverflow exceptions.

ThreadKilled This exception is raised by another thread calling killThread, or by the system if it needs to terminate the thread for some reason.

data IOErrorType

Constructors

AlreadyExists
NoSuchThing
ResourceBusy
ResourceExhausted
EOF
IllegalOperation
PermissionDenied
UserError
UnsatisfiedConstraints
SystemError
ProtocolError
OtherError
InvalidArgument
InappropriateType
HardwareFault
UnsupportedOperation
TimeExpired
ResourceVanished
Interrupted
DynIOError Dynamic

data AsyncException

Asynchronous exceptions

Constructors

HeapOverflow

The program's heap is reaching its limit, and the program should take action to reduce the amount of live data it has. Notes:

It is undefined which thread receives this exception.
GHC currently does not throw HeapOverflow exceptions.

ThreadKilled This exception is raised by another thread calling killThread, or by the system if it needs to terminate the thread for some reason.

data IOErrorType

Constructors

AlreadyExists
NoSuchThing
ResourceBusy
ResourceExhausted
EOF
IllegalOperation
PermissionDenied
UserError
UnsatisfiedConstraints
SystemError
ProtocolError
OtherError
InvalidArgument
InappropriateType
HardwareFault
UnsupportedOperation
TimeExpired
ResourceVanished
Interrupted
DynIOError Dynamic

data ArrayException

Exceptions generated by array operations

Constructors

IndexOutOfBounds String	An attempt was made to index an array outside its declared bounds.
UndefinedElement String	An attempt was made to evaluate an element of an array that had not been initialized.

data ArithException

The type of arithmetic exceptions

Constructors

Overflow
Underflow
LossOfPrecision
DivideByZero
Denormal

data IOErrorType

Constructors

AlreadyExists
NoSuchThing
ResourceBusy
ResourceExhausted
EOF
IllegalOperation
PermissionDenied
UserError
UnsatisfiedConstraints
SystemError
ProtocolError
OtherError
InvalidArgument
InappropriateType
HardwareFault
UnsupportedOperation
TimeExpired
ResourceVanished
Interrupted
DynIOError Dynamic

data IOErrorType

Constructors

AlreadyExists
NoSuchThing
ResourceBusy
ResourceExhausted
EOF
IllegalOperation
PermissionDenied
UserError
UnsatisfiedConstraints
SystemError
ProtocolError
OtherError
InvalidArgument
InappropriateType
HardwareFault
UnsupportedOperation
TimeExpired
ResourceVanished
Interrupted
DynIOError Dynamic

data IOErrorType

Constructors

AlreadyExists
NoSuchThing
ResourceBusy
ResourceExhausted
EOF
IllegalOperation
PermissionDenied
UserError
UnsatisfiedConstraints
SystemError
ProtocolError
OtherError
InvalidArgument
InappropriateType
HardwareFault
UnsupportedOperation
TimeExpired
ResourceVanished
Interrupted
DynIOError Dynamic

data BufferState

Constructors

ReadBuffer
WriteBuffer

data HandleType

Constructors

ClosedHandle
SemiClosedHandle
ReadHandle
WriteHandle
AppendHandle
ReadWriteHandle

bindIO :: IO a -> (a -> IO b) -> IO b

data Buffer

Constructors

Buffer

bufBuf :: RawBuffer
bufRPtr :: !Int
bufWPtr :: !Int
bufSize :: !Int
bufState :: BufferState

data Buffer

Constructors

Buffer

bufBuf :: RawBuffer
bufRPtr :: !Int
bufWPtr :: !Int
bufSize :: !Int
bufState :: BufferState

data Buffer

Constructors

Buffer

bufBuf :: RawBuffer
bufRPtr :: !Int
bufWPtr :: !Int
bufSize :: !Int
bufState :: BufferState

data Buffer

Constructors

Buffer

bufBuf :: RawBuffer
bufRPtr :: !Int
bufWPtr :: !Int
bufSize :: !Int
bufState :: BufferState

data Buffer

Constructors

Buffer

bufBuf :: RawBuffer
bufRPtr :: !Int
bufWPtr :: !Int
bufSize :: !Int
bufState :: BufferState

bufferEmpty :: Buffer -> Bool

bufferFull :: Buffer -> Bool

bufferIsWritable :: Buffer -> Bool

failIO :: String -> IO a

data Handle__

Constructors

Handle__

haFD :: !FD
haType :: HandleType
haIsBin :: Bool
haIsStream :: Bool
haBufferMode :: BufferMode
haFilePath :: FilePath
haBuffer :: !(IORef Buffer)
haBuffers :: !(IORef BufferList)
haOtherSide :: (Maybe (MVar Handle__))

data Handle__

Constructors

Handle__

haFD :: !FD
haType :: HandleType
haIsBin :: Bool
haIsStream :: Bool
haBufferMode :: BufferMode
haFilePath :: FilePath
haBuffer :: !(IORef Buffer)
haBuffers :: !(IORef BufferList)
haOtherSide :: (Maybe (MVar Handle__))

data Handle__

Constructors

Handle__

haFD :: !FD
haType :: HandleType
haIsBin :: Bool
haIsStream :: Bool
haBufferMode :: BufferMode
haFilePath :: FilePath
haBuffer :: !(IORef Buffer)
haBuffers :: !(IORef BufferList)
haOtherSide :: (Maybe (MVar Handle__))

data Handle__

Constructors

Handle__

haFD :: !FD
haType :: HandleType
haIsBin :: Bool
haIsStream :: Bool
haBufferMode :: BufferMode
haFilePath :: FilePath
haBuffer :: !(IORef Buffer)
haBuffers :: !(IORef BufferList)
haOtherSide :: (Maybe (MVar Handle__))

data Handle__

Constructors

Handle__

haFD :: !FD
haType :: HandleType
haIsBin :: Bool
haIsStream :: Bool
haBufferMode :: BufferMode
haFilePath :: FilePath
haBuffer :: !(IORef Buffer)
haBuffers :: !(IORef BufferList)
haOtherSide :: (Maybe (MVar Handle__))

data Handle__

Constructors

Handle__

haFD :: !FD
haType :: HandleType
haIsBin :: Bool
haIsStream :: Bool
haBufferMode :: BufferMode
haFilePath :: FilePath
haBuffer :: !(IORef Buffer)
haBuffers :: !(IORef BufferList)
haOtherSide :: (Maybe (MVar Handle__))

data Handle__

Constructors

Handle__

haFD :: !FD
haType :: HandleType
haIsBin :: Bool
haIsStream :: Bool
haBufferMode :: BufferMode
haFilePath :: FilePath
haBuffer :: !(IORef Buffer)
haBuffers :: !(IORef BufferList)
haOtherSide :: (Maybe (MVar Handle__))

data Handle__

Constructors

Handle__

haFD :: !FD
haType :: HandleType
haIsBin :: Bool
haIsStream :: Bool
haBufferMode :: BufferMode
haFilePath :: FilePath
haBuffer :: !(IORef Buffer)
haBuffers :: !(IORef BufferList)
haOtherSide :: (Maybe (MVar Handle__))

data Handle__

Constructors

Handle__

haFD :: !FD
haType :: HandleType
haIsBin :: Bool
haIsStream :: Bool
haBufferMode :: BufferMode
haFilePath :: FilePath
haBuffer :: !(IORef Buffer)
haBuffers :: !(IORef BufferList)
haOtherSide :: (Maybe (MVar Handle__))

heapOverflow :: Exception

ioError :: Exception -> IO a

A variant of throw that can be used within the IO monad.

Although ioError has a type that is an instance of the type of throw, the two functions are subtly different:

 throw e   `seq` return ()  ===> throw e
 ioError e `seq` return ()  ===> return ()

The first example will cause the exception e to be raised, whereas the second one won't. In fact, ioError will only cause an exception to be raised when it is used within the IO monad. The ioError variant should be used in preference to throw to raise an exception within the IO monad because it guarantees ordering with respect to other IO operations, whereas throw does not.

ioException :: IOException -> IO a

ioToST :: IO a -> ST RealWorld a

data IOException

Constructors

IOError

ioe_handle :: (Maybe Handle)
ioe_type :: IOErrorType
ioe_location :: String
ioe_descr :: String
ioe_filename :: (Maybe FilePath)

data IOException

Constructors

IOError

ioe_handle :: (Maybe Handle)
ioe_type :: IOErrorType
ioe_location :: String
ioe_descr :: String
ioe_filename :: (Maybe FilePath)

data IOException

Constructors

IOError

ioe_handle :: (Maybe Handle)
ioe_type :: IOErrorType
ioe_location :: String
ioe_descr :: String
ioe_filename :: (Maybe FilePath)

data IOException

Constructors

IOError

ioe_handle :: (Maybe Handle)
ioe_type :: IOErrorType
ioe_location :: String
ioe_descr :: String
ioe_filename :: (Maybe FilePath)

data IOException

Constructors

IOError

ioe_handle :: (Maybe Handle)
ioe_type :: IOErrorType
ioe_location :: String
ioe_descr :: String
ioe_filename :: (Maybe FilePath)

liftIO :: IO a -> State# RealWorld -> STret RealWorld a

newIORef :: a -> IO (IORef a)

Build a new IORef

readIORef :: IORef a -> IO a

Read the value of an IORef

returnIO :: a -> IO a

stToIO :: ST RealWorld a -> IO a

stackOverflow :: Exception

thenIO :: IO a -> IO b -> IO b

throw :: Exception -> a

Throw an exception. Exceptions may be thrown from purely functional code, but may only be caught within the IO monad.

unIO :: IO a -> State# RealWorld -> (#State# RealWorld, a#)

unsafeInterleaveIO :: IO a -> IO a

unsafeInterleaveIO allows IO computation to be deferred lazily. When passed a value of type IO a, the IO will only be performed when the value of the a is demanded. This is used to implement lazy file reading, see hGetContents.

unsafePerformIO :: IO a -> a

This is the back door into the IO monad, allowing IO computation to be performed at any time. For this to be safe, the IO computation should be free of side effects and independent of its environment.

If the I/O computation wrapped in unsafePerformIO performs side effects, then the relative order in which those side effects take place (relative to the main I/O trunk, or other calls to unsafePerformIO) is indeterminate.

However, it is less well known that unsafePerformIO is not type safe. For example:

     test :: IORef [a]
     test = unsafePerformIO $ newIORef []
     
     main = do
     	      writeIORef test [42]
     	      bang \<- readIORef test
     	      print (bang :: [Char])

This program will core dump. This problem with polymorphic references is well known in the ML community, and does not arise with normal monadic use of references. There is no easy way to make it impossible once you use unsafePerformIO. Indeed, it is possible to write coerce :: a -> b with the help of unsafePerformIO. So be careful!

userError :: String -> IOError

writeIORef :: IORef a -> a -> IO ()

Write a new value into an IORef

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