Copyright | (C) 2014 I/O Tweag |
---|---|
License | see libraries/base/LICENSE |
Maintainer | cvs-ghc@haskell.org |
Stability | internal |
Portability | non-portable (GHC Extensions) |
Safe Haskell | None |
Language | Haskell2010 |
Symbolic references to values.
References to values are usually implemented with memory addresses, and this is practical when communicating values between the different pieces of a single process.
When values are communicated across different processes running in possibly different machines, though, addresses are no longer useful since each process may use different addresses to store a given value.
To solve such concern, the references provided by this module offer a key that can be used to locate the values on each process. Each process maintains a global table of references which can be looked up with a given key. This table is known as the Static Pointer Table. The reference can then be dereferenced to obtain the value.
The various communicating processes need to aggree on the keys used to refer to the values in the Static Pointer Table, or lookups will fail. Only processes launched from the same program binary are guaranteed to use the same set of keys.
Synopsis
- data StaticPtr a
- deRefStaticPtr :: StaticPtr a -> a
- type StaticKey = Fingerprint
- staticKey :: StaticPtr a -> StaticKey
- unsafeLookupStaticPtr :: StaticKey -> IO (Maybe (StaticPtr a))
- data StaticPtrInfo = StaticPtrInfo {
- spInfoUnitId :: String
- spInfoModuleName :: String
- spInfoSrcLoc :: (Int, Int)
- staticPtrInfo :: StaticPtr a -> StaticPtrInfo
- staticPtrKeys :: IO [StaticKey]
- class IsStatic p where
Documentation
A reference to a value of type a
.
Instances
IsStatic StaticPtr Source # | Since: base-4.9.0.0 |
Defined in GHC.StaticPtr fromStaticPtr :: StaticPtr a -> StaticPtr a Source # |
deRefStaticPtr :: StaticPtr a -> a Source #
Dereferences a static pointer.
type StaticKey = Fingerprint Source #
A key for StaticPtrs
that can be serialized and used with
unsafeLookupStaticPtr
.
data StaticPtrInfo Source #
Miscelaneous information available for debugging purposes.
StaticPtrInfo | |
|
Instances
Show StaticPtrInfo Source # | |
Defined in GHC.StaticPtr |
staticPtrInfo :: StaticPtr a -> StaticPtrInfo Source #
StaticPtrInfo
of the given StaticPtr
.
staticPtrKeys :: IO [StaticKey] Source #
A list of all known keys.