| Copyright | (c) The University of Glasgow 2004 |
|---|---|
| License | BSD-style (see the file libraries/base/LICENSE) |
| Maintainer | libraries@haskell.org |
| Stability | experimental |
| Portability | non-portable (requires STM) |
| Safe Haskell | Trustworthy |
| Language | Haskell2010 |
Control.Concurrent.STM.TVar
Contents
Description
Synopsis
- data TVar a
- newTVar :: a -> STM ( TVar a)
- newTVarIO :: a -> IO ( TVar a)
- readTVar :: TVar a -> STM a
- readTVarIO :: TVar a -> IO a
- writeTVar :: TVar a -> a -> STM ()
- modifyTVar :: TVar a -> (a -> a) -> STM ()
- modifyTVar' :: TVar a -> (a -> a) -> STM ()
- stateTVar :: TVar s -> (s -> (a, s)) -> STM a
- swapTVar :: TVar a -> a -> STM a
- registerDelay :: Int -> IO ( TVar Bool )
- mkWeakTVar :: TVar a -> IO () -> IO ( Weak ( TVar a))
TVars
Shared memory locations that support atomic memory transactions.
newTVarIO :: a -> IO ( TVar a) Source #
IO
version of
newTVar
. This is useful for creating top-level
TVar
s using
unsafePerformIO
, because using
atomically
inside
unsafePerformIO
isn't
possible.
readTVarIO :: TVar a -> IO a Source #
modifyTVar :: TVar a -> (a -> a) -> STM () Source #
Mutate the contents of a
TVar
.
N.B.
, this version is
non-strict.
Since: 2.3
modifyTVar' :: TVar a -> (a -> a) -> STM () Source #
Strict version of
modifyTVar
.
Since: 2.3
stateTVar :: TVar s -> (s -> (a, s)) -> STM a Source #
Like
modifyTVar'
but the function is a simple state transition that can
return a side value which is passed on as the result of the
STM
.
Since: 2.5.0