empty -bytestring +base

empty :: Alternative f => f a
base Control.Applicative
emptySampleVar :: SampleVar a -> IO ()
base Control.Concurrent.SampleVar
If the SampleVar is full, leave it empty. Otherwise, do nothing.
emptyBuffer :: RawBuffer e -> Int -> BufferState -> Buffer e
base GHC.IO.Buffer
emptyWriteBuffer :: BufferedIO dev => dev -> Buffer Word8 -> IO (Buffer Word8)
base GHC.IO.BufferedIO
eNOTEMPTY :: Errno
base Foreign.C.Error
isEmptyChan :: Chan a -> IO Bool
base Control.Concurrent.Chan
Returns True if the supplied Chan is empty.
isEmptyMVar :: MVar a -> IO Bool
base Control.Concurrent.MVar
Check whether a given MVar is empty. Notice that the boolean value returned is just a snapshot of the state of the MVar. By the time you get to react on its result, the MVar may have been filled (or emptied) - so be extremely careful when using this operation. Use tryTakeMVar instead if possible.
isEmptySampleVar :: SampleVar a -> IO Bool
base Control.Concurrent.SampleVar
Returns True if the SampleVar is currently empty. Note that this function is only useful if you know that no other threads can be modifying the state of the SampleVar, because otherwise the state of the SampleVar may have changed by the time you see the result of isEmptySampleVar.
mempty :: Monoid a => a
base Data.Monoid
newEmptyMVar :: IO (MVar a)
base Control.Concurrent.MVar
Create an MVar which is initially empty.
newEmptySampleVar :: IO (SampleVar a)
base Control.Concurrent.SampleVar
Build a new, empty, SampleVar
isEmptyBuffer :: Buffer e -> Bool
base GHC.IO.Buffer