Foreign.C.Types
Copyright | (c) The FFI task force 2001 |
---|---|
License | BSD-style (see the file libraries/base/LICENSE) |
Maintainer | [email protected] |
Stability | provisional |
Portability | portable |
Safe Haskell | Trustworthy |
Language | Haskell2010 |
Description
Mapping of C types to corresponding Haskell types.
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
t
as an argument or result type, the use ofCT
in 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 forCT
has a valid representation in C. -
sizeOf (undefined :: CT)
will yield the same value assizeof (t)
in C. -
alignment (undefined :: CT)
matches the alignment constraint enforced by the C implementation fort
. - The members
peek
andpoke
of theStorable
class map all values ofCT
to the corresponding value oft
and vice versa. - When an instance of
Bounded
is defined forCT
, the values ofminBound
andmaxBound
coincide witht_MIN
andt_MAX
in C. - When an instance of
Eq
orOrd
is 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
, orRealFloat
is 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
Bits
is defined forCT
, the bitwise operation defined by the type class implement the same function as the corresponding bitwise operation in C ont
.
Platform differences
This module contains platform specific information about types. As such, the types presented on this page reflect the platform on which the documentation was generated and may not coincide with the types on your platform.
Integral types
These types are represented as newtype
s 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. (The concrete types of Foreign.C.Types are platform-specific.)
Instances
Haskell type representing the C signed char
type. (The concrete types of Foreign.C.Types are platform-specific.)
Instances
Haskell type representing the C unsigned char
type. (The concrete types of Foreign.C.Types are platform-specific.)
Instances
Haskell type representing the C short
type. (The concrete types of Foreign.C.Types are platform-specific.)
Instances
Haskell type representing the C unsigned short
type. (The concrete types of Foreign.C.Types are platform-specific.)
Instances
Haskell type representing the C int
type. (The concrete types of Foreign.C.Types are platform-specific.)
Instances
Haskell type representing the C unsigned int
type. (The concrete types of Foreign.C.Types are platform-specific.)
Instances
Haskell type representing the C long
type. (The concrete types of Foreign.C.Types are platform-specific.)
Instances
Haskell type representing the C unsigned long
type. (The concrete types of Foreign.C.Types are platform-specific.)
Instances
Haskell type representing the C ptrdiff_t
type. (The concrete types of Foreign.C.Types are platform-specific.)
Instances
Haskell type representing the C size_t
type. (The concrete types of Foreign.C.Types are platform-specific.)
Instances
Haskell type representing the C wchar_t
type. (The concrete types of Foreign.C.Types are platform-specific.)
Instances
newtype CSigAtomic Source
Haskell type representing the C sig_atomic_t
type. (The concrete types of Foreign.C.Types are platform-specific.)
Constructors
CSigAtomic Int32 |
Instances
Haskell type representing the C long long
type. (The concrete types of Foreign.C.Types are platform-specific.)
Instances
Haskell type representing the C unsigned long long
type. (The concrete types of Foreign.C.Types are platform-specific.)
Instances
Haskell type representing the C bool
type. (The concrete types of Foreign.C.Types are platform-specific.)
Since: base-4.10.0.0
Instances
Instances
Instances
Instances
Instances
Numeric types
These types are represented as newtype
s 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. (The concrete types of Foreign.C.Types are platform-specific.)
Instances
Enum CClock | |
Defined in Foreign.C.Types Methodssucc :: CClock -> CClock Source pred :: CClock -> CClock Source toEnum :: Int -> CClock Source fromEnum :: CClock -> Int Source enumFrom :: CClock -> [CClock] Source enumFromThen :: CClock -> CClock -> [CClock] Source enumFromTo :: CClock -> CClock -> [CClock] Source enumFromThenTo :: CClock -> CClock -> CClock -> [CClock] Source | |
Eq CClock | |
Num CClock | |
Ord CClock | |
Defined in Foreign.C.Types | |
Read CClock | |
Real CClock | |
Defined in Foreign.C.Types MethodstoRational :: CClock -> Rational Source | |
Show CClock | |
Storable CClock | |
Defined in Foreign.C.Types MethodssizeOf :: CClock -> Int Source alignment :: CClock -> Int Source peekElemOff :: Ptr CClock -> Int -> IO CClock Source pokeElemOff :: Ptr CClock -> Int -> CClock -> IO () Source peekByteOff :: Ptr b -> Int -> IO CClock Source pokeByteOff :: Ptr b -> Int -> CClock -> IO () Source |
Haskell type representing the C time_t
type. (The concrete types of Foreign.C.Types are platform-specific.)
Instances
Enum CTime | |
Eq CTime | |
Num CTime | |
Ord CTime | |
Defined in Foreign.C.Types | |
Read CTime | |
Real CTime | |
Defined in Foreign.C.Types MethodstoRational :: CTime -> Rational Source | |
Show CTime | |
Storable CTime | |
Defined in Foreign.C.Types |
Haskell type representing the C useconds_t
type. (The concrete types of Foreign.C.Types are platform-specific.)
Since: base-4.4.0.0
Instances
newtype CSUSeconds Source
Haskell type representing the C suseconds_t
type. (The concrete types of Foreign.C.Types are platform-specific.)
Since: base-4.4.0.0
Constructors
CSUSeconds Int64 |
Instances
To convert CTime
to UTCTime
, use the following:
\t -> posixSecondsToUTCTime (realToFrac t :: POSIXTime)
Floating types
These types are represented as newtype
s of Float
and Double
, and are instances of Eq
, Ord
, Num
, Read
, Show
, Enum
, Typeable
, Storable
, Real
, Fractional
, Floating
, RealFrac
and RealFloat
. That does mean that CFloat
's (respectively CDouble
's) instances of Eq
, Ord
, Num
and Fractional
are as badly behaved as Float
's (respectively Double
's).
Haskell type representing the C float
type. (The concrete types of Foreign.C.Types are platform-specific.)
Instances
Haskell type representing the C double
type. (The concrete types of Foreign.C.Types are platform-specific.)
Instances
Other types
Haskell type representing the C FILE
type. (The concrete types of Foreign.C.Types are platform-specific.)
Haskell type representing the C fpos_t
type. (The concrete types of Foreign.C.Types are platform-specific.)
Haskell type representing the C jmp_buf
type. (The concrete types of Foreign.C.Types are platform-specific.)
© The University of Glasgow and others
Licensed under a BSD-style license (see top of the page).
https://downloads.haskell.org/~ghc/8.10.2/docs/html/libraries/base-4.14.1.0/Foreign-C-Types.html