putTMVar :: TMVar a -> a -> STM ()
stm Control.Concurrent.STM.TMVar
Put a value into a TMVar. If the TMVar is currently full, putTMVar will retry.
tryPutTMVar :: TMVar a -> a -> STM Bool
stm Control.Concurrent.STM.TMVar
A version of putTMVar that does not retry. The tryPutTMVar function attempts to put the value a into the TMVar, returning True if it was successful, or False otherwise.