Control.Concurrent.STM.BTChan

Documentation

data BTChan a

A BTChan is a bounded TChan - a FIFO channel using TChan and a transactional variable to limit the number of elements on the channel.

newBTChan :: Int -> STM (BTChan a)

`newBTChan m` make a new bounded TChan of max size m.

newBTChanIO :: Int -> IO (BTChan a)

An IO version of newBTChanIO. This should be useful with unsafePerformIO in the same manner as newTVarIO and newTChanIO are used.

writeBTChan :: BTChan a -> a -> STM ()

Writes the value to the BTChan or blocks if the channel is full.

readBTChan :: BTChan a -> STM a

Reads the next value from the BTChan

isEmptyBTChan :: BTChan a -> STM Bool

Returns True if the supplied TChan is empty.

sizeOfBTChan :: BTChan a -> STM Int

Get the current number of elements in the BTChan.

setMaxOfBTChan :: BTChan a -> Int -> BTChan a

c2 = setMaxOfBTChan c1 mx Using the same underlying TChan, set a new maximum number of messages, mx. If the current size is greater than mx then no messages are dropped, but writes will block till the size goes lower than mx. Using c2 and c1 concurrently is possible, but c2 writes will block at the new maximum while writes to c1 will block at the new, making it biased against whichever writer has the channel with the smaller bound.

maxOfBTChan :: BTChan a -> Int

Get the bound of the BTChan.