Modulerelude-1.2.2.2Haskell2010

Relude.Lifted.IORef

SPDX-License-Identifier : MIT Maintainer : Kowainik xrom.xkov@gmail.com Stability : Stable Portability : Portable

Lifted reexports from Data.IORef module.

1 type
10 values

Packagerelude-1.2.2.2
Exports11
LanguageHaskell2010
LicenceMIT
SourceIORef.hs

newtypenewtype IORef a

A mutable variable in the IO monad.

Example11 expressions

>>> import GHC.Internal.Data.IORef>>> r <- newIORef 0>>> readIORef r0>>> writeIORef r 1>>> readIORef r1>>> atomicWriteIORef r 2>>> readIORef r2>>> modifyIORef' r (+ 1)>>> readIORef r3>>> atomicModifyIORef' r (\a -> (a + 1, ()))>>> readIORef r4

See also STRef and MVar.

Instances3NFData1, Eq, NFData

NFData1 IORefDefined in deepseq-1.5.2.0 · Control.DeepSeq
Eq (IORef a)Defined in ghc-internal-10.0.0 · GHC.Internal.IORef
Pointer equality.
NFData (IORef a)Defined in deepseq-1.5.2.0 · Control.DeepSeq
NOTE: Only strict in the reference and not the referenced value.

valueatomicModifyIORef :: MonadIO m => IORef a -> (a -> (a, b)) -> m b

Lifted version of atomicModifyIORef.

Example3 expressions

>>> ref <- newIORef 42>>> atomicModifyIORef ref (\a -> (a, a + 3))45>>> readIORef ref42

To avoid space-leaks, see atomicModifyIORef' for stricter updates
If you are not interested in the return value, see atomicModifyIORef_

valueatomicModifyIORef' :: MonadIO m => IORef a -> (a -> (a, b)) -> m b

Lifted version of atomicModifyIORef'.

Example3 expressions

>>> ref <- newIORef 42>>> atomicModifyIORef' ref (\a -> (a, a + 3))45>>> readIORef ref42

For lazier updates, see atomicModifyIORef
If you are not interested in the return value, see atomicModifyIORef'_

valueatomicModifyIORef_ :: MonadIO m => IORef a -> (a -> a) -> m ()

Version of atomicModifyIORef that discards return value. Useful when you want to update IORef but not interested in the returning result.

Example3 expressions

>>> ref <- newIORef 42>>> atomicModifyIORef_ ref (`div` 2)>>> readIORef ref21

valueatomicModifyIORef'_ :: MonadIO m => IORef a -> (a -> a) -> m ()

Version of atomicModifyIORef' that discards return value. Useful when you want to update IORef but not interested in the returning result.

Example3 expressions

>>> ref <- newIORef 42>>> atomicModifyIORef'_ ref (`div` 2)>>> readIORef ref21

valueatomicWriteIORef :: MonadIO m => IORef a -> a -> m ()

Lifted version of atomicWriteIORef.

Example3 expressions

>>> ref <- newIORef 42>>> atomicWriteIORef ref 45>>> readIORef ref45

valuemodifyIORef :: MonadIO m => IORef a -> (a -> a) -> m ()

Lifted version of modifyIORef.

Example3 expressions

>>> ref <- newIORef 42>>> modifyIORef ref (\a -> a + 6)>>> readIORef ref48

To avoid space-leaks, see modifyIORef' for stricter updates
For atomic updates, see atomicModifyIORef

valuemodifyIORef' :: MonadIO m => IORef a -> (a -> a) -> m ()

Lifted version of modifyIORef'.

Example3 expressions

>>> ref <- newIORef 42>>> modifyIORef' ref (\a -> a + 3)>>> readIORef ref45

For lazier updates, see modifyIORef
For atomic updates, see atomicModifyIORef'

valuenewIORef :: MonadIO m => a -> m (IORef a)

Lifted version of newIORef.

Example2 expressions

>>> ref <- newIORef False>>> :t refref :: IORef Bool

valuereadIORef :: MonadIO m => IORef a -> m a

Lifted version of readIORef.

Example2 expressions

>>> ref <- newIORef 42>>> readIORef ref42

valuewriteIORef :: MonadIO m => IORef a -> a -> m ()

Lifted version of writeIORef.

Example3 expressions

>>> ref <- newIORef 42>>> writeIORef ref 43>>> readIORef ref43