base-4.9.1.0: Basic libraries

Copyright(c) The FFI task force 2001
Licensesee libraries/base/LICENSE
Maintainerffi@haskell.org
Stabilityprovisional
Portabilityportable
Safe HaskellTrustworthy
LanguageHaskell2010

Foreign.Storable

Description

The module Foreign.Storable provides most elementary support for marshalling and is part of the language-independent portion of the Foreign Function Interface (FFI), and will normally be imported via the Foreign module.

Synopsis

Documentation

class Storable a where #

The member functions of this class facilitate writing values of primitive types to raw memory (which may have been allocated with the above mentioned routines) and reading values from blocks of raw memory. The class, furthermore, includes support for computing the storage requirements and alignment restrictions of storable types.

Memory addresses are represented as values of type Ptr a, for some a which is an instance of class Storable. The type argument to Ptr helps provide some valuable type safety in FFI code (you can't mix pointers of different types without an explicit cast), while helping the Haskell type system figure out which marshalling method is needed for a given pointer.

All marshalling between Haskell and a foreign language ultimately boils down to translating Haskell data structures into the binary representation of a corresponding data structure of the foreign language and vice versa. To code this marshalling in Haskell, it is necessary to manipulate primitive data types stored in unstructured memory blocks. The class Storable facilitates this manipulation on all types for which it is instantiated, which are the standard basic types of Haskell, the fixed size Int types (Int8, Int16, Int32, Int64), the fixed size Word types (Word8, Word16, Word32, Word64), StablePtr, all types from Foreign.C.Types, as well as Ptr.

Minimal complete definition

sizeOf, alignment, (peek | peekElemOff | peekByteOff), (poke | pokeElemOff | pokeByteOff)

Methods

sizeOf :: a -> Int #

Computes the storage requirements (in bytes) of the argument. The value of the argument is not used.

alignment :: a -> Int #

Computes the alignment constraint of the argument. An alignment constraint x is fulfilled by any address divisible by x. The value of the argument is not used.

peekElemOff :: Ptr a -> Int -> IO a #

Read a value from a memory area regarded as an array of values of the same kind. The first argument specifies the start address of the array and the second the index into the array (the first element of the array has index 0). The following equality holds,

peekElemOff addr idx = IOExts.fixIO $ \result ->
  peek (addr `plusPtr` (idx * sizeOf result))

Note that this is only a specification, not necessarily the concrete implementation of the function.

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

Write a value to a memory area regarded as an array of values of the same kind. The following equality holds:

pokeElemOff addr idx x = 
  poke (addr `plusPtr` (idx * sizeOf x)) x

peekByteOff :: Ptr b -> Int -> IO a #

Read a value from a memory location given by a base address and offset. The following equality holds:

peekByteOff addr off = peek (addr `plusPtr` off)

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

Write a value to a memory location given by a base address and offset. The following equality holds:

pokeByteOff addr off x = poke (addr `plusPtr` off) x

peek :: Ptr a -> IO a #

Read a value from the given memory location.

Note that the peek and poke functions might require properly aligned addresses to function correctly. This is architecture dependent; thus, portable code should ensure that when peeking or poking values of some type a, the alignment constraint for a, as given by the function alignment is fulfilled.

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

Write the given value to the given memory location. Alignment restrictions might apply; see peek.

Instances

Storable Bool # 

Methods

sizeOf :: Bool -> Int #

alignment :: Bool -> Int #

peekElemOff :: Ptr Bool -> Int -> IO Bool #

pokeElemOff :: Ptr Bool -> Int -> Bool -> IO () #

peekByteOff :: Ptr b -> Int -> IO Bool #

pokeByteOff :: Ptr b -> Int -> Bool -> IO () #

peek :: Ptr Bool -> IO Bool #

poke :: Ptr Bool -> Bool -> IO () #

Storable Char # 

Methods

sizeOf :: Char -> Int #

alignment :: Char -> Int #

peekElemOff :: Ptr Char -> Int -> IO Char #

pokeElemOff :: Ptr Char -> Int -> Char -> IO () #

peekByteOff :: Ptr b -> Int -> IO Char #

pokeByteOff :: Ptr b -> Int -> Char -> IO () #

peek :: Ptr Char -> IO Char #

poke :: Ptr Char -> Char -> IO () #

Storable Double # 
Storable Float # 

Methods

sizeOf :: Float -> Int #

alignment :: Float -> Int #

peekElemOff :: Ptr Float -> Int -> IO Float #

pokeElemOff :: Ptr Float -> Int -> Float -> IO () #

peekByteOff :: Ptr b -> Int -> IO Float #

pokeByteOff :: Ptr b -> Int -> Float -> IO () #

peek :: Ptr Float -> IO Float #

poke :: Ptr Float -> Float -> IO () #

Storable Int # 

Methods

sizeOf :: Int -> Int #

alignment :: Int -> Int #

peekElemOff :: Ptr Int -> Int -> IO Int #

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

peekByteOff :: Ptr b -> Int -> IO Int #

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

peek :: Ptr Int -> IO Int #

poke :: Ptr Int -> Int -> IO () #

Storable Int8 # 

Methods

sizeOf :: Int8 -> Int #

alignment :: Int8 -> Int #

peekElemOff :: Ptr Int8 -> Int -> IO Int8 #

pokeElemOff :: Ptr Int8 -> Int -> Int8 -> IO () #

peekByteOff :: Ptr b -> Int -> IO Int8 #

pokeByteOff :: Ptr b -> Int -> Int8 -> IO () #

peek :: Ptr Int8 -> IO Int8 #

poke :: Ptr Int8 -> Int8 -> IO () #

Storable Int16 # 

Methods

sizeOf :: Int16 -> Int #

alignment :: Int16 -> Int #

peekElemOff :: Ptr Int16 -> Int -> IO Int16 #

pokeElemOff :: Ptr Int16 -> Int -> Int16 -> IO () #

peekByteOff :: Ptr b -> Int -> IO Int16 #

pokeByteOff :: Ptr b -> Int -> Int16 -> IO () #

peek :: Ptr Int16 -> IO Int16 #

poke :: Ptr Int16 -> Int16 -> IO () #

Storable Int32 # 

Methods

sizeOf :: Int32 -> Int #

alignment :: Int32 -> Int #

peekElemOff :: Ptr Int32 -> Int -> IO Int32 #

pokeElemOff :: Ptr Int32 -> Int -> Int32 -> IO () #

peekByteOff :: Ptr b -> Int -> IO Int32 #

pokeByteOff :: Ptr b -> Int -> Int32 -> IO () #

peek :: Ptr Int32 -> IO Int32 #

poke :: Ptr Int32 -> Int32 -> IO () #

Storable Int64 # 

Methods

sizeOf :: Int64 -> Int #

alignment :: Int64 -> Int #

peekElemOff :: Ptr Int64 -> Int -> IO Int64 #

pokeElemOff :: Ptr Int64 -> Int -> Int64 -> IO () #

peekByteOff :: Ptr b -> Int -> IO Int64 #

pokeByteOff :: Ptr b -> Int -> Int64 -> IO () #

peek :: Ptr Int64 -> IO Int64 #

poke :: Ptr Int64 -> Int64 -> IO () #

Storable Word # 

Methods

sizeOf :: Word -> Int #

alignment :: Word -> Int #

peekElemOff :: Ptr Word -> Int -> IO Word #

pokeElemOff :: Ptr Word -> Int -> Word -> IO () #

peekByteOff :: Ptr b -> Int -> IO Word #

pokeByteOff :: Ptr b -> Int -> Word -> IO () #

peek :: Ptr Word -> IO Word #

poke :: Ptr Word -> Word -> IO () #

Storable Word8 # 

Methods

sizeOf :: Word8 -> Int #

alignment :: Word8 -> Int #

peekElemOff :: Ptr Word8 -> Int -> IO Word8 #

pokeElemOff :: Ptr Word8 -> Int -> Word8 -> IO () #

peekByteOff :: Ptr b -> Int -> IO Word8 #

pokeByteOff :: Ptr b -> Int -> Word8 -> IO () #

peek :: Ptr Word8 -> IO Word8 #

poke :: Ptr Word8 -> Word8 -> IO () #

Storable Word16 # 
Storable Word32 # 
Storable Word64 # 
Storable () # 

Methods

sizeOf :: () -> Int #

alignment :: () -> Int #

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

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

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

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

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

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

Storable Fingerprint # 
Storable CUIntMax # 
Storable CIntMax # 
Storable CUIntPtr # 
Storable CIntPtr # 
Storable CSUSeconds # 
Storable CUSeconds # 
Storable CTime # 

Methods

sizeOf :: CTime -> Int #

alignment :: CTime -> Int #

peekElemOff :: Ptr CTime -> Int -> IO CTime #

pokeElemOff :: Ptr CTime -> Int -> CTime -> IO () #

peekByteOff :: Ptr b -> Int -> IO CTime #

pokeByteOff :: Ptr b -> Int -> CTime -> IO () #

peek :: Ptr CTime -> IO CTime #

poke :: Ptr CTime -> CTime -> IO () #

Storable CClock # 
Storable CSigAtomic # 
Storable CWchar # 
Storable CSize # 

Methods

sizeOf :: CSize -> Int #

alignment :: CSize -> Int #

peekElemOff :: Ptr CSize -> Int -> IO CSize #

pokeElemOff :: Ptr CSize -> Int -> CSize -> IO () #

peekByteOff :: Ptr b -> Int -> IO CSize #

pokeByteOff :: Ptr b -> Int -> CSize -> IO () #

peek :: Ptr CSize -> IO CSize #

poke :: Ptr CSize -> CSize -> IO () #

Storable CPtrdiff # 
Storable CDouble # 
Storable CFloat # 
Storable CULLong # 
Storable CLLong # 
Storable CULong # 
Storable CLong # 

Methods

sizeOf :: CLong -> Int #

alignment :: CLong -> Int #

peekElemOff :: Ptr CLong -> Int -> IO CLong #

pokeElemOff :: Ptr CLong -> Int -> CLong -> IO () #

peekByteOff :: Ptr b -> Int -> IO CLong #

pokeByteOff :: Ptr b -> Int -> CLong -> IO () #

peek :: Ptr CLong -> IO CLong #

poke :: Ptr CLong -> CLong -> IO () #

Storable CUInt # 

Methods

sizeOf :: CUInt -> Int #

alignment :: CUInt -> Int #

peekElemOff :: Ptr CUInt -> Int -> IO CUInt #

pokeElemOff :: Ptr CUInt -> Int -> CUInt -> IO () #

peekByteOff :: Ptr b -> Int -> IO CUInt #

pokeByteOff :: Ptr b -> Int -> CUInt -> IO () #

peek :: Ptr CUInt -> IO CUInt #

poke :: Ptr CUInt -> CUInt -> IO () #

Storable CInt # 

Methods

sizeOf :: CInt -> Int #

alignment :: CInt -> Int #

peekElemOff :: Ptr CInt -> Int -> IO CInt #

pokeElemOff :: Ptr CInt -> Int -> CInt -> IO () #

peekByteOff :: Ptr b -> Int -> IO CInt #

pokeByteOff :: Ptr b -> Int -> CInt -> IO () #

peek :: Ptr CInt -> IO CInt #

poke :: Ptr CInt -> CInt -> IO () #

Storable CUShort # 
Storable CShort # 
Storable CUChar # 
Storable CSChar # 
Storable CChar # 

Methods

sizeOf :: CChar -> Int #

alignment :: CChar -> Int #

peekElemOff :: Ptr CChar -> Int -> IO CChar #

pokeElemOff :: Ptr CChar -> Int -> CChar -> IO () #

peekByteOff :: Ptr b -> Int -> IO CChar #

pokeByteOff :: Ptr b -> Int -> CChar -> IO () #

peek :: Ptr CChar -> IO CChar #

poke :: Ptr CChar -> CChar -> IO () #

Storable IntPtr # 
Storable WordPtr # 
Storable Fd # 

Methods

sizeOf :: Fd -> Int #

alignment :: Fd -> Int #

peekElemOff :: Ptr Fd -> Int -> IO Fd #

pokeElemOff :: Ptr Fd -> Int -> Fd -> IO () #

peekByteOff :: Ptr b -> Int -> IO Fd #

pokeByteOff :: Ptr b -> Int -> Fd -> IO () #

peek :: Ptr Fd -> IO Fd #

poke :: Ptr Fd -> Fd -> IO () #

Storable CSsize # 
Storable CPid # 

Methods

sizeOf :: CPid -> Int #

alignment :: CPid -> Int #

peekElemOff :: Ptr CPid -> Int -> IO CPid #

pokeElemOff :: Ptr CPid -> Int -> CPid -> IO () #

peekByteOff :: Ptr b -> Int -> IO CPid #

pokeByteOff :: Ptr b -> Int -> CPid -> IO () #

peek :: Ptr CPid -> IO CPid #

poke :: Ptr CPid -> CPid -> IO () #

Storable COff # 

Methods

sizeOf :: COff -> Int #

alignment :: COff -> Int #

peekElemOff :: Ptr COff -> Int -> IO COff #

pokeElemOff :: Ptr COff -> Int -> COff -> IO () #

peekByteOff :: Ptr b -> Int -> IO COff #

pokeByteOff :: Ptr b -> Int -> COff -> IO () #

peek :: Ptr COff -> IO COff #

poke :: Ptr COff -> COff -> IO () #

Storable CMode # 

Methods

sizeOf :: CMode -> Int #

alignment :: CMode -> Int #

peekElemOff :: Ptr CMode -> Int -> IO CMode #

pokeElemOff :: Ptr CMode -> Int -> CMode -> IO () #

peekByteOff :: Ptr b -> Int -> IO CMode #

pokeByteOff :: Ptr b -> Int -> CMode -> IO () #

peek :: Ptr CMode -> IO CMode #

poke :: Ptr CMode -> CMode -> IO () #

Storable CIno # 

Methods

sizeOf :: CIno -> Int #

alignment :: CIno -> Int #

peekElemOff :: Ptr CIno -> Int -> IO CIno #

pokeElemOff :: Ptr CIno -> Int -> CIno -> IO () #

peekByteOff :: Ptr b -> Int -> IO CIno #

pokeByteOff :: Ptr b -> Int -> CIno -> IO () #

peek :: Ptr CIno -> IO CIno #

poke :: Ptr CIno -> CIno -> IO () #

Storable CDev # 

Methods

sizeOf :: CDev -> Int #

alignment :: CDev -> Int #

peekElemOff :: Ptr CDev -> Int -> IO CDev #

pokeElemOff :: Ptr CDev -> Int -> CDev -> IO () #

peekByteOff :: Ptr b -> Int -> IO CDev #

pokeByteOff :: Ptr b -> Int -> CDev -> IO () #

peek :: Ptr CDev -> IO CDev #

poke :: Ptr CDev -> CDev -> IO () #

(Storable a, Integral a) => Storable (Ratio a) # 

Methods

sizeOf :: Ratio a -> Int #

alignment :: Ratio a -> Int #

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

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

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

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

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

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

Storable (StablePtr a) # 

Methods

sizeOf :: StablePtr a -> Int #

alignment :: StablePtr a -> Int #

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

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

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

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

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

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

Storable (Ptr a) # 

Methods

sizeOf :: Ptr a -> Int #

alignment :: Ptr a -> Int #

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

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

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

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

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

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

Storable (FunPtr a) # 

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 () #

Storable a => Storable (Complex a) # 

Methods

sizeOf :: Complex a -> Int #

alignment :: Complex a -> Int #

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

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

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

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

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

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

Storable a => Storable (Identity a) # 

Methods

sizeOf :: Identity a -> Int #

alignment :: Identity a -> Int #

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

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

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

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

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

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

Storable a => Storable (Const k a b) # 

Methods

sizeOf :: Const k a b -> Int #

alignment :: Const k a b -> Int #

peekElemOff :: Ptr (Const k a b) -> Int -> IO (Const k a b) #

pokeElemOff :: Ptr (Const k a b) -> Int -> Const k a b -> IO () #

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

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

peek :: Ptr (Const k a b) -> IO (Const k a b) #

poke :: Ptr (Const k a b) -> Const k a b -> IO () #