Modulestreamly-core-0.3.1Haskell2010

Streamly.Internal.Data.IORef

A mutable variable in a mutation capable monad (IO) holding a Unboxed value. This allows fast modification because of unboxed storage.

Multithread Consistency Notes

In general, any value that straddles a machine word cannot be guaranteed to be consistently read from another thread without a lock. GHC heap objects are always machine word aligned, therefore, a IORef is also word aligned. On a 64-bit platform, writing a 64-bit aligned type from one thread and reading it from another thread should give consistent old or new value. The same holds true for 32-bit values on a 32-bit platform.

1 type
6 values

Packagestreamly-core-0.3.1
Exports7
LanguageHaskell2010
LicenceBSD-3-Clause
SourceIORef.hs

newtypenewtype IORef a

An IORef holds a single Unbox-able value.

valuenewIORef :: Unbox a => a -> IO (IORef a)

Create a new IORef.

Pre-release

valuewriteIORef :: Unbox a => IORef a -> a -> IO ()

Write a value to an IORef.

Pre-release

valuemodifyIORef' :: Unbox a => IORef a -> (a -> a) -> IO ()

Modify the value of an IORef using a function with strict application.

Pre-release

valuereadIORef :: Unbox a => IORef a -> IO a

Read a value from an IORef.

Pre-release

valuepollGenericIORef :: (MonadIO m, Unbox a) => IORef a -> Stream m a

Internal, do not use.

valuepollIORefInt :: MonadIO m => IORef Int -> Stream m Int

Generate a stream by continuously reading the IORef.

This operation reads the IORef without any synchronization. It can be assumed to be atomic because the size fits into machine register size. We are assuming that compiler uses single instructions to access the memory. It may read stale values though until caches are synchronised in a multiprocessor architecture.

Pre-release