| Copyright | (c) The FFI task force 2001 |
|---|---|
| License | BSD-style (see the file libraries/base/LICENSE) |
| Maintainer | ffi@haskell.org |
| Stability | provisional |
| Portability | portable |
| Safe Haskell | Trustworthy |
| Language | Haskell2010 |
Foreign.C.Types
Description
Mapping of C types to corresponding Haskell types.
- newtype CChar = CChar Int8
- newtype CSChar = CSChar Int8
- newtype CUChar = CUChar Word8
- newtype CShort = CShort Int16
- newtype CUShort = CUShort Word16
- newtype CInt = CInt Int32
- newtype CUInt = CUInt Word32
- newtype CLong = CLong Int64
- newtype CULong = CULong Word64
- newtype CPtrdiff = CPtrdiff Int64
- newtype CSize = CSize Word64
- newtype CWchar = CWchar Int32
- newtype CSigAtomic = CSigAtomic Int32
- newtype CLLong = CLLong Int64
- newtype CULLong = CULLong Word64
- newtype CIntPtr = CIntPtr Int64
- newtype CUIntPtr = CUIntPtr Word64
- newtype CIntMax = CIntMax Int64
- newtype CUIntMax = CUIntMax Word64
- newtype CClock = CClock Int64
- newtype CTime = CTime Int64
- newtype CUSeconds = CUSeconds Word32
- newtype CSUSeconds = CSUSeconds Int64
- newtype CFloat = CFloat Float
- newtype CDouble = CDouble Double
- data CFile
- data CFpos
- data CJmpBuf
Representations of C types
These types are needed to accurately represent C function prototypes,
in order to access C library interfaces in Haskell. The Haskell system
is not required to represent those types exactly as C does, but the
following guarantees are provided concerning a Haskell type CT
representing a C type t:
- If a C function prototype has
tas an argument or result type, the use ofCTin the corresponding position in a foreign declaration permits the Haskell program to access the full range of values encoded by the C type; and conversely, any Haskell value forCThas a valid representation in C. sizeOf(undefined:: CT)sizeof (t)in C.alignment(undefined:: CT)t.- The members
peekandpokeof theStorableclass map all values ofCTto the corresponding value oftand vice versa. - When an instance of
Boundedis defined forCT, the values ofminBoundandmaxBoundcoincide witht_MINandt_MAXin C. - When an instance of
EqorOrdis defined forCT, the predicates defined by the type class implement the same relation as the corresponding predicate in C ont. - When an instance of
Num,Read,Integral,Fractional,Floating,RealFrac, orRealFloatis defined forCT, the arithmetic operations defined by the type class implement the same function as the corresponding arithmetic operations (if available) in C ont. - When an instance of
Bitsis defined forCT, the bitwise operation defined by the type class implement the same function as the corresponding bitwise operation in C ont.
Integral types
These types are are represented as newtypes of
types in Data.Int and Data.Word, and are instances of
Eq, Ord, Num, Read,
Show, Enum, Typeable, Storable,
Bounded, Real, Integral and
Bits.
Haskell type representing the C char type.
Haskell type representing the C signed char type.
Haskell type representing the C unsigned char type.
Haskell type representing the C short type.
Haskell type representing the C unsigned short type.
Haskell type representing the C int type.
Haskell type representing the C unsigned int type.
Haskell type representing the C long type.
Haskell type representing the C unsigned long type.
Haskell type representing the C ptrdiff_t type.
Haskell type representing the C size_t type.
Haskell type representing the C wchar_t type.
newtype CSigAtomic Source
Haskell type representing the C sig_atomic_t type.
Constructors
| CSigAtomic Int32 |
Haskell type representing the C long long type.
Haskell type representing the C unsigned long long type.
Numeric types
These types are represented as newtypes of basic
foreign types, and are instances of
Eq, Ord, Num, Read,
Show, Enum, Typeable and Storable.
Haskell type representing the C clock_t type.
Haskell type representing the C time_t type.
Haskell type representing the C useconds_t type.
Since: 4.4.0.0
newtype CSUSeconds Source
Haskell type representing the C suseconds_t type.
Since: 4.4.0.0
Constructors
| CSUSeconds Int64 |
To convert CTime to UTCTime, use the following:
\t -> posixSecondsToUTCTime (realToFrac t :: POSIXTime)
Floating types
These types are are represented as newtypes of
Float and Double, and are instances of
Eq, Ord, Num, Read,
Show, Enum, Typeable, Storable,
Real, Fractional, Floating,
RealFrac and RealFloat.
Haskell type representing the C float type.
Haskell type representing the C double type.