Control.Concurrent.STM.CTVar

Transactional variables, for use with MonadSTM.

CTVars

newCTVar :: MonadSTM m => a -> m (CTVar m a)

Create a new CTVar containing the given value.

readCTVar :: MonadSTM m => CTVar m a -> m a

Return the current value stored in a CTVar.

writeCTVar :: MonadSTM m => CTVar m a -> a -> m ()

Write the supplied value into the CTVar.

modifyCTVar :: MonadSTM m => CTVar m a -> (a -> a) -> m ()

Mutate the contents of a CTVar. This is non-strict.

modifyCTVar' :: MonadSTM m => CTVar m a -> (a -> a) -> m ()

Mutate the contents of a CTVar strictly.

swapCTVar :: MonadSTM m => CTVar m a -> a -> m a

Swap the contents of a CTVar, returning the old value.