base-4.16.0.0: Basic libraries
Copyright(c) The FFI Task Force 2000-2002
Licensesee libraries/base/LICENSE
Maintainerffi@haskell.org
Stabilityinternal
Portabilitynon-portable (GHC Extensions)
Safe HaskellUnsafe
LanguageHaskell2010

GHC.Ptr

Description

The Ptr and FunPtr types and operations.

Synopsis

Documentation

data Ptr a Source #

A value of type Ptr a represents a pointer to an object, or an array of objects, which may be marshalled to or from Haskell values of type a.

The type a will often be an instance of class Storable which provides the marshalling operations. However this is not essential, and you can provide your own operations to access the pointer. For example you might write small foreign functions to get or set the fields of a C struct.

Constructors

Ptr Addr# 

Instances

Instances details
Generic1 (URec (Ptr ()) :: k -> Type) # 
Instance details

Defined in GHC.Generics

Associated Types

type Rep1 (URec (Ptr ())) :: k -> Type Source #

Methods

from1 :: forall (a :: k0). URec (Ptr ()) a -> Rep1 (URec (Ptr ())) a Source #

to1 :: forall (a :: k0). Rep1 (URec (Ptr ())) a -> URec (Ptr ()) a Source #

Eq (Ptr a) #

Since: base-2.1

Instance details

Defined in GHC.Ptr

Methods

(==) :: Ptr a -> Ptr a -> Bool Source #

(/=) :: Ptr a -> Ptr a -> Bool Source #

Data a => Data (Ptr a) #

Since: base-4.8.0.0

Instance details

Defined in Data.Data

Methods

gfoldl :: (forall d b. Data d => c (d -> b) -> d -> c b) -> (forall g. g -> c g) -> Ptr a -> c (Ptr a) Source #

gunfold :: (forall b r. Data b => c (b -> r) -> c r) -> (forall r. r -> c r) -> Constr -> c (Ptr a) Source #

toConstr :: Ptr a -> Constr Source #

dataTypeOf :: Ptr a -> DataType Source #

dataCast1 :: Typeable t => (forall d. Data d => c (t d)) -> Maybe (c (Ptr a)) Source #

dataCast2 :: Typeable t => (forall d e. (Data d, Data e) => c (t d e)) -> Maybe (c (Ptr a)) Source #

gmapT :: (forall b. Data b => b -> b) -> Ptr a -> Ptr a Source #

gmapQl :: (r -> r' -> r) -> r -> (forall d. Data d => d -> r') -> Ptr a -> r Source #

gmapQr :: forall r r'. (r' -> r -> r) -> r -> (forall d. Data d => d -> r') -> Ptr a -> r Source #

gmapQ :: (forall d. Data d => d -> u) -> Ptr a -> [u] Source #

gmapQi :: Int -> (forall d. Data d => d -> u) -> Ptr a -> u Source #

gmapM :: Monad m => (forall d. Data d => d -> m d) -> Ptr a -> m (Ptr a) Source #

gmapMp :: MonadPlus m => (forall d. Data d => d -> m d) -> Ptr a -> m (Ptr a) Source #

gmapMo :: MonadPlus m => (forall d. Data d => d -> m d) -> Ptr a -> m (Ptr a) Source #

Ord (Ptr a) #

Since: base-2.1

Instance details

Defined in GHC.Ptr

Methods

compare :: Ptr a -> Ptr a -> Ordering Source #

(<) :: Ptr a -> Ptr a -> Bool Source #

(<=) :: Ptr a -> Ptr a -> Bool Source #

(>) :: Ptr a -> Ptr a -> Bool Source #

(>=) :: Ptr a -> Ptr a -> Bool Source #

max :: Ptr a -> Ptr a -> Ptr a Source #

min :: Ptr a -> Ptr a -> Ptr a Source #

Show (Ptr a) #

Since: base-2.1

Instance details

Defined in GHC.Ptr

Methods

showsPrec :: Int -> Ptr a -> ShowS Source #

show :: Ptr a -> String Source #

showList :: [Ptr a] -> ShowS Source #

Foldable (UAddr :: Type -> Type) #

Since: base-4.9.0.0

Instance details

Defined in Data.Foldable

Methods

fold :: Monoid m => UAddr m -> m Source #

foldMap :: Monoid m => (a -> m) -> UAddr a -> m Source #

foldMap' :: Monoid m => (a -> m) -> UAddr a -> m Source #

foldr :: (a -> b -> b) -> b -> UAddr a -> b Source #

foldr' :: (a -> b -> b) -> b -> UAddr a -> b Source #

foldl :: (b -> a -> b) -> b -> UAddr a -> b Source #

foldl' :: (b -> a -> b) -> b -> UAddr a -> b Source #

foldr1 :: (a -> a -> a) -> UAddr a -> a Source #

foldl1 :: (a -> a -> a) -> UAddr a -> a Source #

toList :: UAddr a -> [a] Source #

null :: UAddr a -> Bool Source #

length :: UAddr a -> Int Source #

elem :: Eq a => a -> UAddr a -> Bool Source #

maximum :: Ord a => UAddr a -> a Source #

minimum :: Ord a => UAddr a -> a Source #

sum :: Num a => UAddr a -> a Source #

product :: Num a => UAddr a -> a Source #

Traversable (UAddr :: Type -> Type) #

Since: base-4.9.0.0

Instance details

Defined in Data.Traversable

Methods

traverse :: Applicative f => (a -> f b) -> UAddr a -> f (UAddr b) Source #

sequenceA :: Applicative f => UAddr (f a) -> f (UAddr a) Source #

mapM :: Monad m => (a -> m b) -> UAddr a -> m (UAddr b) Source #

sequence :: Monad m => UAddr (m a) -> m (UAddr a) Source #

Storable (Ptr a) #

Since: base-2.1

Instance details

Defined in Foreign.Storable

Methods

sizeOf :: Ptr a -> Int Source #

alignment :: Ptr a -> Int Source #

peekElemOff :: Ptr (Ptr a) -> Int -> IO (Ptr a) Source #

pokeElemOff :: Ptr (Ptr a) -> Int -> Ptr a -> IO () Source #

peekByteOff :: Ptr b -> Int -> IO (Ptr a) Source #

pokeByteOff :: Ptr b -> Int -> Ptr a -> IO () Source #

peek :: Ptr (Ptr a) -> IO (Ptr a) Source #

poke :: Ptr (Ptr a) -> Ptr a -> IO () Source #

Functor (URec (Ptr ()) :: Type -> Type) #

Since: base-4.9.0.0

Instance details

Defined in GHC.Generics

Methods

fmap :: (a -> b) -> URec (Ptr ()) a -> URec (Ptr ()) b Source #

(<$) :: a -> URec (Ptr ()) b -> URec (Ptr ()) a Source #

Eq (URec (Ptr ()) p) #

Since: base-4.9.0.0

Instance details

Defined in GHC.Generics

Methods

(==) :: URec (Ptr ()) p -> URec (Ptr ()) p -> Bool Source #

(/=) :: URec (Ptr ()) p -> URec (Ptr ()) p -> Bool Source #

Ord (URec (Ptr ()) p) #

Since: base-4.9.0.0

Instance details

Defined in GHC.Generics

Methods

compare :: URec (Ptr ()) p -> URec (Ptr ()) p -> Ordering Source #

(<) :: URec (Ptr ()) p -> URec (Ptr ()) p -> Bool Source #

(<=) :: URec (Ptr ()) p -> URec (Ptr ()) p -> Bool Source #

(>) :: URec (Ptr ()) p -> URec (Ptr ()) p -> Bool Source #

(>=) :: URec (Ptr ()) p -> URec (Ptr ()) p -> Bool Source #

max :: URec (Ptr ()) p -> URec (Ptr ()) p -> URec (Ptr ()) p Source #

min :: URec (Ptr ()) p -> URec (Ptr ()) p -> URec (Ptr ()) p Source #

Generic (URec (Ptr ()) p) # 
Instance details

Defined in GHC.Generics

Associated Types

type Rep (URec (Ptr ()) p) :: Type -> Type Source #

Methods

from :: URec (Ptr ()) p -> Rep (URec (Ptr ()) p) x Source #

to :: Rep (URec (Ptr ()) p) x -> URec (Ptr ()) p Source #

data URec (Ptr ()) (p :: k) #

Used for marking occurrences of Addr#

Since: base-4.9.0.0

Instance details

Defined in GHC.Generics

data URec (Ptr ()) (p :: k) = UAddr {}
type Rep1 (URec (Ptr ()) :: k -> Type) #

Since: base-4.9.0.0

Instance details

Defined in GHC.Generics

type Rep1 (URec (Ptr ()) :: k -> Type) = D1 ('MetaData "URec" "GHC.Generics" "base" 'False) (C1 ('MetaCons "UAddr" 'PrefixI 'True) (S1 ('MetaSel ('Just "uAddr#") 'NoSourceUnpackedness 'NoSourceStrictness 'DecidedLazy) (UAddr :: k -> Type)))
type Rep (URec (Ptr ()) p) #

Since: base-4.9.0.0

Instance details

Defined in GHC.Generics

type Rep (URec (Ptr ()) p) = D1 ('MetaData "URec" "GHC.Generics" "base" 'False) (C1 ('MetaCons "UAddr" 'PrefixI 'True) (S1 ('MetaSel ('Just "uAddr#") 'NoSourceUnpackedness 'NoSourceStrictness 'DecidedLazy) (UAddr :: Type -> Type)))

data FunPtr a Source #

A value of type FunPtr a is a pointer to a function callable from foreign code. The type a will normally be a foreign type, a function type with zero or more arguments where

A value of type FunPtr a may be a pointer to a foreign function, either returned by another foreign function or imported with a a static address import like

foreign import ccall "stdlib.h &free"
  p_free :: FunPtr (Ptr a -> IO ())

or a pointer to a Haskell function created using a wrapper stub declared to produce a FunPtr of the correct type. For example:

type Compare = Int -> Int -> Bool
foreign import ccall "wrapper"
  mkCompare :: Compare -> IO (FunPtr Compare)

Calls to wrapper stubs like mkCompare allocate storage, which should be released with freeHaskellFunPtr when no longer required.

To convert FunPtr values to corresponding Haskell functions, one can define a dynamic stub for the specific foreign type, e.g.

type IntFunction = CInt -> IO ()
foreign import ccall "dynamic"
  mkFun :: FunPtr IntFunction -> IntFunction

Constructors

FunPtr Addr# 

Instances

Instances details
Eq (FunPtr a) # 
Instance details

Defined in GHC.Ptr

Methods

(==) :: FunPtr a -> FunPtr a -> Bool Source #

(/=) :: FunPtr a -> FunPtr a -> Bool Source #

Ord (FunPtr a) # 
Instance details

Defined in GHC.Ptr

Methods

compare :: FunPtr a -> FunPtr a -> Ordering Source #

(<) :: FunPtr a -> FunPtr a -> Bool Source #

(<=) :: FunPtr a -> FunPtr a -> Bool Source #

(>) :: FunPtr a -> FunPtr a -> Bool Source #

(>=) :: FunPtr a -> FunPtr a -> Bool Source #

max :: FunPtr a -> FunPtr a -> FunPtr a Source #

min :: FunPtr a -> FunPtr a -> FunPtr a Source #

Show (FunPtr a) #

Since: base-2.1

Instance details

Defined in GHC.Ptr

Storable (FunPtr a) #

Since: base-2.1

Instance details

Defined in Foreign.Storable

Methods

sizeOf :: FunPtr a -> Int Source #

alignment :: FunPtr a -> Int Source #

peekElemOff :: Ptr (FunPtr a) -> Int -> IO (FunPtr a) Source #

pokeElemOff :: Ptr (FunPtr a) -> Int -> FunPtr a -> IO () Source #

peekByteOff :: Ptr b -> Int -> IO (FunPtr a) Source #

pokeByteOff :: Ptr b -> Int -> FunPtr a -> IO () Source #

peek :: Ptr (FunPtr a) -> IO (FunPtr a) Source #

poke :: Ptr (FunPtr a) -> FunPtr a -> IO () Source #

nullPtr :: Ptr a Source #

The constant nullPtr contains a distinguished value of Ptr that is not associated with a valid memory location.

castPtr :: Ptr a -> Ptr b Source #

The castPtr function casts a pointer from one type to another.

plusPtr :: Ptr a -> Int -> Ptr b Source #

Advances the given address by the given offset in bytes.

alignPtr :: Ptr a -> Int -> Ptr a Source #

Given an arbitrary address and an alignment constraint, alignPtr yields the next higher address that fulfills the alignment constraint. An alignment constraint x is fulfilled by any address divisible by x. This operation is idempotent.

minusPtr :: Ptr a -> Ptr b -> Int Source #

Computes the offset required to get from the second to the first argument. We have

p2 == p1 `plusPtr` (p2 `minusPtr` p1)

nullFunPtr :: FunPtr a Source #

The constant nullFunPtr contains a distinguished value of FunPtr that is not associated with a valid memory location.

castFunPtr :: FunPtr a -> FunPtr b Source #

Casts a FunPtr to a FunPtr of a different type.

Unsafe functions

castFunPtrToPtr :: FunPtr a -> Ptr b Source #

Casts a FunPtr to a Ptr.

Note: this is valid only on architectures where data and function pointers range over the same set of addresses, and should only be used for bindings to external libraries whose interface already relies on this assumption.

castPtrToFunPtr :: Ptr a -> FunPtr b Source #

Casts a Ptr to a FunPtr.

Note: this is valid only on architectures where data and function pointers range over the same set of addresses, and should only be used for bindings to external libraries whose interface already relies on this assumption.