Data.Atomics.Counter.Foreign

This implementation stores an unboxed counter and uses FFI operations to modify its contents.

Documentation

type AtomicCounter = ForeignPtr Int

type CTicket = Int

newCounter :: IO AtomicCounter

Create a new counter initialized to zero.

incrCounter :: AtomicCounter -> IO Int

Try repeatedly until we successfully increment the counter. Returns the original value before the increment.

readCounterForCAS :: AtomicCounter -> IO CTicket

peekCTicket :: CTicket -> Int

readCounter :: AtomicCounter -> IO Int

writeCounter :: AtomicCounter -> Int -> IO ()

Make a non-atomic write to the counter. No memory-barrier.

casCounter :: AtomicCounter -> CTicket -> Int -> IO (Bool, CTicket)