TVar package:concurrency

Transactional variables, for use with MonadSTM. Deviations: There is no Eq instance for MonadSTM the TVar type. Furthermore, the newTVarIO and mkWeakTVar functions are not provided.

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

Mutate the contents of a TVar strictly.

Create a new TVar containing the given value.

newTVar = newTVarN ""

Create a new TVar containing the given value, but it is given a name which may be used to present more useful debugging information. If an empty name is given, a counter starting from 0 is used. If names conflict, successive TVars with the same name are given a numeric suffix, counting up from 1.

newTVarN _ = newTVar

Return the current value stored in a TVar.

Read the current value stored in a TVar. This may be implemented differently for speed.

readTVarConc = atomically . readTVar

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.

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

Write the supplied value into the TVar.

Create a TVar. This may be implemented differently for speed.

newTVarConc = atomically . newTVar