planet-mitchell-0.0.0: Planet Mitchell

Safe HaskellSafe
LanguageHaskell2010

Ptr.Fun

Synopsis

Documentation

data FunPtr a #

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
Instances
NFData1 FunPtr

Since: deepseq-1.4.3.0

Instance details

Defined in Control.DeepSeq

Methods

liftRnf :: (a -> ()) -> FunPtr a -> () #

Eq (FunPtr a) 
Instance details

Defined in GHC.Ptr

Methods

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

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

Ord (FunPtr a) 
Instance details

Defined in GHC.Ptr

Methods

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

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

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

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

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

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

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

Show (FunPtr a)

Since: base-2.1

Instance details

Defined in GHC.Ptr

Methods

showsPrec :: Int -> FunPtr a -> ShowS #

show :: FunPtr a -> String #

showList :: [FunPtr a] -> ShowS #

Hashable (FunPtr a) 
Instance details

Defined in Data.Hashable.Class

Methods

hashWithSalt :: Int -> FunPtr a -> Int #

hash :: FunPtr a -> Int #

Storable (FunPtr a)

Since: base-2.1

Instance details

Defined in Foreign.Storable

Methods

sizeOf :: FunPtr a -> Int #

alignment :: FunPtr a -> Int #

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

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

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

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

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

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

NFData (FunPtr a)

Since: deepseq-1.4.2.0

Instance details

Defined in Control.DeepSeq

Methods

rnf :: FunPtr a -> () #

Prim (FunPtr a) 
Instance details

Defined in Data.Primitive.Types

nullFunPtr :: FunPtr a #

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

castFunPtr :: FunPtr a -> FunPtr b #

Casts a FunPtr to a FunPtr of a different type.

castFunPtrToPtr :: FunPtr a -> Ptr b #

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 #

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.

freeHaskellFunPtr :: FunPtr a -> IO () #

Release the storage associated with the given FunPtr, which must have been obtained from a wrapper stub. This should be called whenever the return value from a foreign import wrapper function is no longer required; otherwise, the storage it uses will leak.

type FinalizerPtr a = FunPtr (Ptr a -> IO ()) #

A finalizer is represented as a pointer to a foreign function that, at finalisation time, gets as an argument a plain pointer variant of the foreign pointer that the finalizer is associated with.

Note that the foreign function must use the ccall calling convention.

type FinalizerEnvPtr env a = FunPtr (Ptr env -> Ptr a -> IO ()) #

finalizerFree :: FinalizerPtr a #

A pointer to a foreign function equivalent to free, which may be used as a finalizer (cf ForeignPtr) for storage allocated with malloc, mallocBytes, realloc or reallocBytes.